Separation of acids from chemical reaction mixtures by means of ionic liquids

ABSTRACT

Process for preparing aminodihalophosphines, diaminohalophosphines, triaminophosphines, phosphorous ester diamides, aminophosphines, diaminophosphines, phosphorous ester amide halides and aminophosphine halides with elimination of an acid in the presence of an auxiliary base, wherein the auxiliary base b) and the acid form a salt which is liquid at temperatures at which the desired product is not significantly decomposed during the process of separating off the liquid salt and c) the salt of the auxiliary base forms two immiscible liquid phases with the desired product or the solution of the desired product in a suitable solvent.

The present invention relates to a process for the simplified separationof acids from reaction mixtures by means of an ionic liquid.

A chemist frequently has the problem of neutralizing or trapping acidsliberated during a chemical reaction or separating acids from reactionmixtures. Examples of reactions in which acids are liberated during thecourse of the reaction are the silylation of alcohols or amines by meansof halosilanes, the phosphorylation of amines or alcohols by means ofphosphorus halides, the formation of sulfonic esters or amides fromalcohols or amines and sulfonic acid chlorides or anhydrides,eliminations and substitutions.

These reactions liberate acids, which is why an auxiliary base whichgenerally does not participate as reactant in the actual reaction isadditionally added. In general, it is necessary to bind the liberatedacids by means of this base to form a salt in order to suppresssecondary and subsequent reactions or simply to remove the acid from thedesired reaction product and possibly return it to the process. If thesalts of the bases used are not separated off initially, they can alsobe worked up in the presence of the desired product, e.g. by addition ofa further, stronger base such as an aqueous caustic alkali, e.g. sodiumhydroxide or potassium hydroxide. This forms the salt of the strongerbase added in this step. In addition, the base originally used isliberated. In general, these two components, i.e. the salt of thestronger base and the initially employed base (auxiliary base) which hasnow been liberated likewise have to be separated off from the desiredproduct. In this procedure, it is often a disadvantage that the desiredproduct which is present in the work-up can be decomposed by the addedstronger base itself or further substances in this base, e.g. the waterin an aqueous caustic alkali.

The salts of the auxiliary base with the acid are generally not solublein organic solvents and have high melting points, so that in organicmedia they form suspensions which are more difficult to handle than, forexample, liquids. It would therefore be desirable to be able to separateoff the salts of the auxiliary bases in liquid form. In addition, theknown process engineering disadvantages of suspensions would beeliminated. These are, for example, the formation of encrustations,reduction of heat transfer, poor mixing and stirrability and theformation of regions where the concentration is too high or too low andhot spots.

For processes carried out in industry, the prior art accordingly has thefollowing disadvantages:

-   1) addition of two auxiliary bases, viz. the auxiliary base and a    further strong base, and the resulting need to separate two    auxiliaries from the desired product and from one another,-   2) handling of suspensions and-   3) separating off the salt of the strong base as a solid.

However, a phase separation by means of a liquid-liquid phase separationwhich is simple from a process engineering point of view would bedesirable.

DE-A 197 24 884 and DE-A 198 26 936 disclose processes for preparingcarbonyldiimidazoles by phosgenation of imidazoles, in which theresulting hydrochloride of the imidazole used as starting material isseparated as a melt from the reaction mixture. In DE-A 198 26 936, it ispointed out on page 3, line 5, that the hydrochloride of the imidazoleis, surprisingly, liquid at 110-130° C. and melts significantly belowthe melting point of 158-161° C. reported in the literature. As reasonsfor this, the inventors suggest either the formation of a eutecticmixture of the imidazole hydrochloride with the desired productcarbonyldiimidazole or the formation of a ternary mixture of theimidazole hydrochloride, the desired product carbonyldiimidazole and thechlorobenzene solvent. Although the imidazole hydrochloride should nothave been present in liquid form, this was surprisingly the case in thisspecific system. Applicability of this concept to reactions other thanthe phosgenation of imidazoles is not described.

It is an object of the present invention to find a simplified processfor separating off acids, in which the salt formed from an addedauxiliary base and an acid can be separated off by means of a simpleliquid-liquid phase separation and which can be applied to otherchemical reactions or to the removal of acids which are present inmixtures but are not liberated during a chemical reaction.

We have found that this object is achieved by a process for separatingacids from reaction mixtures by means of an auxiliary base, in which theauxiliary base

-   b) and the acid form a salt which is liquid at temperatures at which    the desired product is not significantly decomposed during the    process of separating off the liquid salt and-   c) the salt of the auxiliary base forms two immiscible liquid phases    with the desired product or the solution of the desired product in a    suitable solvent.

A person skilled in the art will know that the separation of a liquidphase from a second liquid phase is considerably simpler in processengineering terms than is a solid separation.

An advantage for industrial purposes of the process of the presentinvention is that the auxiliary can be separated off by means of asimple liquid-liquid phase separation, so that the process engineeringcomplications associated with handling solids are eliminated.

The work-up of the auxiliaries can be carried out in the absence of thedesired product, so that the latter is subjected to less stress.

The invention described here achieves the abovementioned object byreaction mixtures containing or subsequently being admixed withauxiliary bases whose salts with acids liberated during the course ofthe reaction or added acids, i.e. acids which are not liberated duringthe reaction, are liquid under the reaction conditions and/or work-upconditions and form a phase which is immiscible with the (possiblydissolved) desired product. Such liquid salts are often referred to asionic liquids. The acids to be bound can either be present in free formin the reaction mixture or can form a complex or an adduct with thedesired product or another substance present in the reaction mixture.Lewis acids in particular tend to form complexes with substances such asketones. These complexes can be split by means of the auxiliary base, sothat the salt of the auxiliary base and the Lewis acid to be separatedoff is formed according to the invention.

The auxiliary bases can be inorganic or organic bases, preferablyorganic bases.

Furthermore, mixtures or solutions of auxiliary bases can be used toachieve the object of the invention.

For the purposes of the present invention, immiscible or not misciblemeans that at least two liquid phases separated by a phase interface(boundary) are formed.

If the pure desired product is completely or largely miscible with thesalt of the auxiliary base and the acid, an auxiliary, e.g. a solvent,can also be added to the desired product to achieve demixing or areduction in solubility. This is useful when, for example, thesolubility of the salt in the desired product or vice versa is 20% byweight or more, preferably 15% by weight or more, particularlypreferably 10% by weight or more and very particularly preferably 5% byweight of more. The solubility is determined under the conditions of therespective separation. The solubility is preferably determined at atemperature which is above the melting point of the salt and below thelowest of the following temperatures, particularly preferably 10° C.below the lowest and very particularly preferably 20° C. below thelowest:

-   -   boiling point of the desired product    -   boiling point of the solvent    -   temperature of significant decomposition of the desired product.

The solvent is regarded as suitable when the mixture of desired productand solvent is able to dissolve less than the abovementioned amounts ofthe salt, or the salt is able to dissolve less than the abovementionedamounts of the desired product or a mixture of desired product andsolvent. Solvents which can be used are, for example, benzene, toluene,o-, m- or p-xylene, mesitylene, cyclohexane, cyclopentane, pentane,hexane, heptane, octane, petroleum ether, acetone, isobutyl methylketone, diethyl ketone, diethyl ether, tert-butyl methyl ether,tert-butyl ethyl ether, tetrahydrouran, dioxane, ethyl acetate, methylacetate, dimethylformamide, dimethyl sulfoxide, acetonitrile,chloroform, dichloromethane, methylchloroform or mixtures thereof.

The desired product is generally a nonpolar organic or inorganiccompound.

Chemical reactions on which the invention can be based are all reactionsin which acids are liberated, with the exception of phosgenations,particularly preferably with the exception of acylations, i.e. reactionsof acid halides and carboxylic anhydrides.

Reactions to which the process of the present invention can be appliedare, for example,

-   -   alkylations using alkyl or aralkyl halides, e.g. methyl        chloride, methyl iodide, benzyl chloride, 1,2-dichloroethane or        2-chloroethanol,    -   acylations, i.e. reactions of acid halides and carboxylic        anhydrides, of any substrates, for example alcohols or amines,    -   silylations, i.e. reactions with compounds containing at least        one Si-Hal bond, e.g. SiCl₄, (H₃C)₂SiCl₂ or trimethylsilyl        chloride,    -   phosphorylations, i.e. reactions with compounds containing at        least one P-Hal bond, e.g. PCl₃, PCl₅, POCl₃, POBr₃,        dichlorophenylphosphine or diphenylchlorophosphine, as are        likewise described by, for example, Chojnowski et al., loc.        cit.,    -   sulfurations, i.e. sulfidations, sulfonations and sulfations,        using, for example, sulfuryl chloride (SO₂Cl₂), thionyl chloride        (SOCl₂), chlorosulfonic acid (ClSO₃H), sulfonic acid halides,        such as p-toluenesulfonyl chloride, methanesulfonyl chloride or        trifluoromethanesulfonyl chloride, or sulfonic anhydrides, as        are described, for example, by Dobrynin, V. N. et al. Bioorg.        Khim. 9(5), 1983, 706-10,    -   eliminations in which a C═C double bond is formed with        elimination of an acid such as HCl, HBr, acetic acid or        para-toluenesulfonic acid, or    -   deprotonations in which an acidic hydrogen atom is abstracted by        the auxiliary base.

Among the types of reaction mentioned, preference is given toalkylations, silylations, phosphorylations, sulfurations, acylationswith the exception of phosgenations, and eliminations. Particularpreference is given to silylations, phosphorylations and sulfurations.

Furthermore, the process of the present invention can also be employedto separate off an acid from a reaction mixture to which an acid whichis not liberated during the reaction has been added, for example toadjust the pH or to catalyze a reaction. Thus, for example, Lewis acidswhich have been used as catalysts for Friedel-Crafts alkylations oracylations can be separated off in a simple way.

The acids to be separated off according to the present invention can beBrönsted acids and Lewis acids. The designations of acids as Brönstedand Lewis acids is described in Hollemann-Wiberg, Lehrbuch derAnorganischen Chemie, 91st-100th edition, Walter de Gruyter, Berlin N.Y.1985, p. 235 or p. 239. Lewis acids for the purposes of the presentinvention also include the Lewis acids used as Friedel-Crafts catalystsand described in George A. Olah, Friedel-Crafts and Related Reactions,Vol. I, 191 to 197, 201 and 284-90 (1963). Examples which may bementioned are aluminum trichloride (AlCl₃), iron(III) chloride (FeCl₃),aluminum tribromide (AlBr₃) and zinc chloride (ZnCl₂).

In general, the Lewis acids which can be separated off according to thepresent invention contain cationic forms of the metals of groups Ib,IIb, IIIa, IIIb, IVa, IVb, Va, Vb, VIb, VIIb and VIII of the PeriodicTable of the Elements and the rare earths, for example lanthanum,cerium, praseodymium, neodymium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium.

Particular mention may be made of zinc, cadmium, beryllium, boron,aluminum, gallium, indium, thallium, titanium, zirconium, hafnium,erbium, germanium, tin, vanadium, niobium, scandium, yttrium, chromium,molybdenum, tungsten, manganese, rhenium, palladium, thorium, iron,copper and cobalt. Preference is given to boron, zinc, cadmium,titanium, tin, iron, cobalt.

Possible counterions for the Lewis acid are F⁻, Cl⁻, ClO⁻, ClO₃ ⁻, ClO₄⁻, Br⁻, J⁻, JO₃ ⁻, CN⁻, OCN⁻, SCN⁻, NO₂ ⁻, NO₃ ⁻, HCO₃ ⁻, CO₃ ²⁻, S²⁻,SH⁻, HSO₃ ⁻, SO₃ ²⁻, HSO₄ ⁻, SO₄ ²⁻, S₂O₂ ²⁻, S₂O₄ ²⁻, S₂O₅ ²⁻, S₂O₆ ²⁻,S₂O₇ ²⁻, S₂O₈ ²⁻, H₂PO₂ ⁻, H₂PO₄ ⁻, HPO₄ ²⁻, PO₄ ³⁻, P₂O₇ ⁴⁻,dithiocarbamate, salicylate, (OC_(n)H_(2n+1))⁻, (C_(n)H_(2n−1)O₂),(C_(n)H_(2n−3)O₂)⁻ and (C_(n+1)H_(2n−2)O₄)²⁻, where n is from 1 to 20,methanesulfonate (CH₃SO₃ ⁻), trifluoromethanesulfonate (CF₃SO₃ ⁻),toluenesulfonate (CH₃C₆H₄SO₃ ⁻), benzenesulfonate (C₆H₅SO₃ ⁻), hydroxide(OH⁻), anions of aromatic acids such as benzoic acid, phthalic acid andthe like and 1,3-dicarbonyl compounds.

Mention may also be made of carboxylates, in particular formate,acetate, trifluoroacetate, propionate, hexanoate and 2-ethylhexanoate,stearate and oxalate, acetylacetonate, tartrate, acrylate andmethacrylate, preferably formate, acetate, propionate, oxalate,acetylacetonate, acrylate and methacrylate.

Further possibilities are borohydrides and organoboron compounds of theformulae BR″″₃ and B(OR″″)₃, where the radicals R″″ are each,independently of one another, hydrogen, C₁-C₁₈-alkyl, C₂-C₁₈-alkyl whichmay be interrupted by one or more oxygen and/or sulfur atoms and/or oneor more substituted or unsubstituted imino groups, C₆-C₁₂-aryl,C₅-C₁₂-cycloalkyl or a five- to six-membered oxygen-, nitrogen- and/orsulfur-containing heterocycle or two of them together form anunsaturated, saturated or aromatic ring which may be interrupted by oneor more oxygen and/or sulfur atoms and/or one or more substituted orunsubstituted imino groups, where the radicals mentioned may each besubstituted by functional groups, aryl, alkyl, aryloxy, alkyloxy,halogen, heteroatoms and/or heterocycles. The radicals R″″ may also bejoined to one another.

Preferred examples of Lewis acids are, in addition to the AlCl₃, FeCl₃,AlBr₃ and ZnCl₂ mentioned above, BeCl₂, ZnBr₂, Znl₂, ZnSO₄, CuCl₂, CuCl,Cu(O₃SCF₃)₂, CoCl₂, CoI₂, FeI₂, FeCl₂, FeCl₂(THF)₂, TiCl₄(THF)₂, TiCl₄,TiCl₃, CiTi(OiPr)₃, SnCl₂, SnCl₄, Sn(SO₄), Sn(SO₄)₂, MnCl₂, MnBr₂,ScCl₃, BPh₃, BCl₃, BBr₃, BF₃.OEt₂, BF₃.OMe₂, BF₃.MeOH, BF₃.CH₃COOH,BF₃.CH₃CN, B(CF₃COO)₃, B(OEt)₃, B(OMe)₃, B(OiPr)₃, PhB(OH)₂,3-MeO-PhB(OH)₂, 4-MeO-PhB(OH)₂, 3-F-PhB(OH)₂, 4-F-PhB(OH)₂, (C₂H₅)₃Al,(C₂H₅)₂AlCl, (C₂H₅)AlCl₂, (C₈H₁₇)AlCl₂, (C₈H₁₇)₂AlCl, (iso-C₄H₉)₂AlCl,Ph₂AlCl, PhAlCl₂, Al(acac)₃, Al(OiPr)₃, Al(OnBu)₃, Al(OsecBu)₃,Al(OEt)₃, GaCl₃, ReCl₅, ZrCl₄, NbCl₅, VCl₃, CrCl₂, MoCl₅, YCl₃, CdCl₂,CdBr₂, SbCl₃, SbCl₅, BiCl₃, ZrCl₄, UCl₄, LaCl₃, CeCl₃, Er(O₃SCF₃),Yb(O₂CCF₃)₃, SmCl₃, SmI₂, B(C₆H₅)₃, TaCl₅.

The Lewis acids can be stabilized by alkali metal halides or alkalineearth metal halides, for example LiCl or NaCl. For this purpose, thealkali metal or alkaline earth metal halides are mixed into the Lewisacid in a molar ratio of 0-100:1.

For the purposes of the present text, halogen or Hal is fluorine (F),chlorine (Cl), bromine (Br) or iodine (I), preferably chlorine.

Compounds reacted in a silylation, phosphorylation or sulfuration are ingeneral compounds which have at least one free O—H, S—H or N—H bond,possibly after deprotonation by the auxiliary base.

As auxiliary base, it is possible according to the present invention touse a compound which reacts with the acid liberated during the reactionto form a salt which

-   b) is liquid at temperatures at which the desired product is not    significantly decomposed during the process of separating off the    liquid salt and-   c) forms two immiscible liquid phases with the desired product or    the solution of the desired product in a suitable solvent.

Preference is given to auxiliary base which

-   a) do not participate in the reaction as reactant.

Furthermore, this auxiliary base can, additionally and preferably,

-   d) function simultaneously as a nucleophilic catalyst in the    reaction, i.e. it increases the reaction rate of the reaction    compared to the reaction carried out in the absence of an auxiliary    base by a factor of at least 1.5, preferably at least two,    particularly preferably at least five, very particularly preferably    at least ten and in particular at least twenty.

Such compounds which can be used as bases may contain phosphorus, sulfuror nitrogen atoms, for example at least one nitrogen atom, preferablyfrom one to ten nitrogen atoms, particularly preferably from one to fivenitrogen atoms, very particularly preferably from one to three nitrogenatoms and in particular one or two nitrogen atoms. Further heteroatomssuch as oxygen, sulfur or phosphorus atoms may also be present.

Preference is given to compounds containing at least one five- tosix-membered heterocycle which contains at least one nitrogen atom andpossibly an oxygen or sulfur atom, particularly preferably compoundscontaining at least one five- to six-membered heterocycle in which one,two or three nitrogen atoms and one sulfur or oxygen atom are present,very particularly preferably compounds of this type containing twonitrogen atoms.

Particularly preferred compounds have a molecular weight of less than1000 g/mol, very particularly preferably less than 500 g/mol and inparticular less than 250 g/mol.

Furthermore, preferred bases are compounds selected from among thecompounds of the formulae (Ia) to (Ir),

and also oligomers or polymers comprising these structures,whereR¹, R², R³, R⁴, R⁵ and R⁶ are each, independently of one another,hydrogen, C₁-C₁₈-alkyl, C₂-C₁₈-alkyl which may be interrupted by one ormore oxygen and/or sulfur atoms and/or one or more substituted orunsubstituted imino groups, C₆-C₁₂-aryl, C₅-C₁₂-cycloalkyl or a five- tosix-membered, oxygen-, nitrogen- and/or sulfur-containing heterocycle ortwo of them may together form an unsaturated, saturated or aromatic ringwhich may be interrupted by one or more oxygen and/or sulfur atomsand/or one or more substituted or unsubstituted imino groups, where theradicals mentioned may each be substituted by functional groups, aryl,alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles.

In the above formulae,

C₁-C₁₈-alkyl which may be substituted by functional groups, aryl, alkyl,aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is, forexample, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl,2,4,4-trimethylpentyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl,1,1-dimethylpropyl, 1,1-dimethylbutyl, 1,1,3,3-tetramethylbutyl, benzyl,1-phenylethyl, 2-phenylethyl, α,α-dimethylbenzyl, benzhydryl,p-tolylmethyl, 1-(p-butylphenyl)ethyl, p-chlorobenzyl,2,4-dichlorobenzyl, p-methoxybenzyl, m-ethoxybenzyl, 2-cyanoethyl,2-cyanopropyl, 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl,2-butoxycarbonylpropyl, 1,2-di(methoxycarbonyl)ethyl, 2-methoxyethyl,2-ethoxyethyl, 2-butoxyethyl, diethoxymethyl, diethoxyethyl,1,3-dioxolan-2-yl, 1,3-dioxan-2-yl, 2-methyl-1,3-dioxolan-2-yl,4-methyl-1,3-dioxolan-2-yl, 2-isopropoxyethyl, 2-butoxypropyl,2-octyloxyethyl, chloromethyl, 2-chloroethyl, trichloromethyl,trifluoromethyl, 1,1-dimethyl-2-chloroethyl, 2-methoxyisopropyl,2-ethoxyethyl, butylthiomethyl, 2-dodecylthioethyl, 2-phenylthioethyl,2,2,2-trifluoroethyl, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl,4-hydroxybutyl, 6-hydroxyhexyl, 2-aminoethyl, 2-aminopropyl,3-aminopropyl, 4-aminobutyl, 6-aminohexyl, 2-methylaminoethyl,2-methylaminopropyl, 3-methylaminopropyl, 4-methylaminobutyl,6-methylaminohexyl, 2-dimethylaminoethyl, 2-dimethylaminopropyl,3-dimethylaminopropyl, 4-dimethylaminobutyl, 6-dimethylaminohexyl,2-hydroxy-2,2-dimethylethyl, 2-phenoxyethyl, 2-phenoxypropyl,3-phenoxypropyl, 4-phenoxybutyl, 6-phenoxyhexyl, 2-methoxyethyl,2-methoxypropyl, 3-methoxypropyl, 4-methoxybutyl, 6-methoxyhexyl,2-ethoxyethyl, 2-ethoxypropyl, 3-ethoxypropyl, 4-ethoxybutyl or6-ethoxyhexyl, and

C₂-C₁₈-alkyl which may be interrupted by one or more oxygen and/orsulfur atoms and/or one or more substituted or unsubstituted iminogroups is, for example, 5-hydroxy-3-oxapentyl, 8-hydroxy-3,6-dioxaoctyl,11-hydroxy-3,6,9-trioxaundecyl, 7-hydroxy-4-oxaheptyl,11-hydroxy-4,8-dioxaundecyl, 15-hydroxy-4,8,12-trioxapentadecyl,9-hydroxy-5-oxanonyl, 14-hydroxy-5,10-oxatetradecyl,5-methoxy-3-oxapentyl, 8-methoxy-3,6-dioxaoctyl,11-methoxy-3,6,9-trioxaundecyl, 7-methoxy-4-oxaheptyl,11-methoxy-4,8-dioxaundecyl, 15-methoxy-4,8,12-trioxapentadecyl,9-methoxy-5-oxanonyl, 14-methoxy-5,10-oxatetradecyl,5-ethoxy-3-oxapentyl, 8-ethoxy-3,6-dioxaoctyl,11-ethoxy-3,6,9-trioxaundecyl, 7-ethoxy-4-oxaheptyl,11-ethoxy-4,8-dioxaundecyl, 15-ethoxy-4,8,12-trioxapentadecyl,9-ethoxy-5-oxanonyl or 14-ethoxy-5,10-oxatetradecyl.

If two radicals form a ring, these radicals can together become1,3-propylene, 1,4-butylene, 2-oxa-1,3-propylene, 1-oxa-1,3-propylene,2-oxa-1,3-propylene, 1-oxa-1,3-propenylene, 1-aza-1,3-propenylene,1-C₁-C₄-alkyl-1-aza-1,3-propenylene, 1,4-buta-1,3-dienylene,1-aza-1,4-buta-1,3-dienylene or 2-aza-1,4-buta-1,3-dienylene.

The number of oxygen and/or sulfur atoms and/or imino groups is notrestricted. In general, it is not more than 5 in the one radical,preferably not more than 4 and very particularly preferably not morethan 3.

Furthermore, at least one carbon atom, preferably at least two, is/aregenerally located between two heteroatoms.

Substituted and unsubstituted imino groups can be, for example, imino,methylimino, isopropylimino, n-butylimino or tert-butylimino.

Furthermore,

functional groups are carboxy, carboxamide, hydroxy,di(C₁-C₄-alkyl)amino, C₁-C₄-alkyloxycarbonyl, cyano or C₁-C₄-alkyloxy,

C₆-C₁₂-aryl which may be substituted by functional groups, aryl, alkyl,aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is, forexample, phenyl, tolyl, xylyl, α-naphthyl, β-naphthyl, 4-biphenylyl,chlorophenyl, dichlorophenyl, trichlorophenyl, difluorophenyl,methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl,diethylphenyl, isopropylphenyl, tert-butylphenyl, dodecylphenyl,methoxyphenyl, dimethoxyphenyl, ethoxyphenyl, hexyloxyphenyl,methylnaphthyl, isopropylnaphthyl, chloronaphthyl, ethoxynaphthyl,2,6-dimethylphenyl, 2,4,6-trimethylphenyl, 2,6-dimethoxyphenyl,2,6-dichlorophenyl, 4-bromophenyl, 2- or 4-nitrophenyl, 2,4- or2,6-dinitrophenyl, 4-dimethylaminophenyl, 4-acetylphenyl,methoxyethylphenyl or ethoxymethylphenyl,

C₅-C₁₂-cycloalkyl which may be substituted by functional groups, aryl,alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles is,for example, cyclopentyl, cyclohexyl, cyclooctyl, cyclododecyl,methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl,dimethylcyclohexyl, diethylcyclohexyl, butylcyclohexyl,methoxycyclohexyl, dimethoxycyclohexyl, diethoxycyclohexyl,butylthiocyclohexyl, chlorocyclohexyl, dichlorocyclohexyl,dichlorocyclopentyl or a saturated or unsaturated bicyclic system suchas norbornyl or norbornenyl,

a five- to six-membered, oxygen-, nitrogen- and/or sulfur-containingheterocycle is, for example, furyl, thiophenyl, pyrryl, pyridyl,indolyl, benzoxazolyl, dioxolyl, dioxyl, benzimidazolyl, benzthiazolyl,dimethylpyridyl, methylquinolyl, dimethylpyrryl, methoxyfuryl,dimethoxypyridyl, difluoropyridyl, methylthiophenyl, isopropylthiophenylor tert-butylthiophenyl and

C₁-C₄-alkyl is, for example, methyl, ethyl, propyl, isopropyl, n-butyl,sec-butyl or tert-butyl.

Preference is given to R¹, R², R³, R⁴, R⁵ and R⁶ each being,independently of one another, hydrogen, methyl, ethyl, n-butyl,2-hydroxyethyl, 2-cyanoethyl, 2-(methoxycarbonyl)ethyl,2-(ethoxycarbonyl)ethyl, 2-(n-butoxycarbonyl)ethyl, dimethylamino,diethylamino and chlorine.

Particularly preferred pyridines (Ia) are those in which one of theradicals R¹ to R⁵ is methyl, ethyl or chlorine and all others arehydrogen, or R³ is dimethylamino and all others are hydrogen or all arehydrogen or R² is carboxy or carboxamide and all others are hydrogen orR¹ and R² or R² and R³ are 1,4-buta-1,3-dienylene and all others arehydrogen.

Particularly preferred pyridazines (Ib) are those in which one of theradicals R¹ to R⁴ is methyl or ethyl and all others are hydrogen or allare hydrogen.

Particularly preferred pyrimidines (Ic) are those in which R² to R⁴ areeach hydrogen or methyl and R¹ is hydrogen, methyl or ethyl, or R² andR⁴ are each methyl, R³ is hydrogen and R¹ is hydrogen, methyl or ethyl.

Particularly preferred pyrazines (Id) are those in which R¹ to R⁴ areall methyl or all hydrogen.

Particularly preferred imidazoles (Ie) are those in which, independentlyof one another,

R¹ is selected from among methyl, ethyl, n-propyl, n-butyl, n-pentyl,n-octyl, 2-hydroxyethyl or 2-cyanoethyl and

R² to R⁴ are each, independently of one another, hydrogen, methyl orethyl.

Particularly preferred 1H-pyrazoles (If) are those in which,independently of one another

R¹ is selected from among hydrogen, methyl and ethyl,

R², R³ and R⁴ are selected from among hydrogen or methyl.

Particularly preferred 3H-pyrazoles (Ig) are those in which,independently of one another,

R¹ is selected from among hydrogen, methyl and ethyl,

R², R³ and R⁴ are selected from among hydrogen and methyl.

Particularly preferred 4H-pyrazoles (Ih) are those in which,independently of one another,

R¹ to R⁴ are selected from among hydrogen and methyl.

Particularly preferred 1-pyrazolines (Ii) are those in which,independently of one another,

R¹ to R⁶ are selected from among hydrogen and methyl.

Particularly preferred 2-pyrazolines (Ij) are those in which,independently of one another,

R¹ is selected from among hydrogen, methyl, ethyl and phenyl, and

R² to R⁶ are selected from among hydrogen and methyl.

Particularly preferred 3-pyrazolines (Ik) are those in which,independently of one another,

R¹ and R² are selected from among hydrogen, methyl, ethyl and phenyl,and

R³ to R⁶ are selected from among hydrogen and methyl.

Particularly preferred imidazolines (II) are those in which,independently of one another,

R¹ and R² are selected from among hydrogen, methyl, ethyl, n-butyl andphenyl,

R³ and R⁴ are selected from among hydrogen, methyl and ethyl, and

R⁵ and R⁶ are selected from among hydrogen and methyl.

Particularly preferred imidazolines (Im) are those in which,independently of one another,

R¹ and R² are selected from among hydrogen, methyl and ethyl, and

R³ to R⁶ are selected from among hydrogen and methyl.

Particularly preferred imidazolines (In) are those in which,independently of one another,

R¹, R² and R³ are selected from among hydrogen, methyl and ethyl, and

R⁴ to R⁶ are selected from among hydrogen and methyl.

Particularly preferred thiazoles (Io) and oxazoles (Ip) are those inwhich, independently of one another,

R¹ is selected from among hydrogen, methyl, ethyl and phenyl, and

R² and R³ are selected from among hydrogen and methyl.

Particularly preferred 1,2,4-triazoles (Iq) are those in which,independently of one another,

R¹ and R² are selected from among hydrogen, methyl, ethyl and phenyl,and

R³ is selected from among hydrogen, methyl and phenyl.

Particularly preferred 1,2,3-triazoles (Ir) are those in which,independently of one another,

R¹ is selected from among hydrogen, methyl and ethyl, and

R² and R³ are selected from among hydrogen and methyl or

R² and R³ together form 1,4-buta-1,3-dienylene and all others arehydrogen.

Among these, the pyridines and the imidazoles are preferred.

Very particularly preferred bases are 3-chloropyridine,4-dimethylaminopyridine, 2-ethyl-4-aminopyridine, 2-methylpyridine(α-picoline), 3-methylpyridine (β-picoline), 4-methylpyridine(γ-picoline), 2-ethylpyridine, 2-ethyl-6-methylpyridine, quinoline,isoquinoline, 1-C₁-C₄-alkylimidazole, 1-methylimidazole,1,2-dimethylimidazole, 1-n-butylimidazole, 1,4,5-trimethylimidazole,1,4-dimethylimidazole, imidazole, 2-methylimidazole,1-butyl-2-methylimidazole, 4-methylimidazole, 1-n-pentylimidazole,1-n-hexylimidazole, 1-n-octylimidazole, 1-(2′-aminoethyl)imidazole,2-ethyl-4-methylimidazole, 1-vinylimidazole, 2-ethylimidazole,1-(2′-cyanoethyl)imidazole and benzotriazole.

Special preference is given to 1-n-butylimidazole, 1-methylimidazole,2-methylpyridine and 2-ethylpyridine.

Also suitable are tertiary amines of the formula (XI),NR^(a)R^(b)R^(c)  (XI),whereR^(a), R^(b) and R^(c) are each, independently of one another,C₁-C₁₈-alkyl, C₂-C₁₈-alkyl which may be interrupted by one or moreoxygen and/or sulfur atoms and/or one or more substituted orunsubstituted imino groups, C₆-C₁₂-aryl or C₅-C₁₂-cycloalkyl or a five-to six-membered, oxygen-, nitrogen- and/or sulfur-containing heterocycleor two of them together form an unsaturated, saturated or aromatic ringwhich may be interrupted by one or more oxygen and/or sulfur atomsand/or one or more substituted or unsubstituted imino groups, where theradicals mentioned may each be substituted by functional groups, aryl,alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles, withthe proviso that

-   -   at least two of the three radicals R^(a), R^(b) and R^(c) are        different and    -   the radicals R^(a), R^(b) and R^(c) together have at least 8,        preferably at least 10, particularly preferably at least 12 and        very particularly preferably at least 13, carbon atoms.

Preference is given to R^(a), R^(b) and R^(c) each being, independentlyof one another, C₁-C₁₈-alkyl, C₆-C₁₂-aryl or C₅-C₁₂-cycloalkyl,particularly preferably C₁-C₁₈-alkyl, where the radicals mentioned mayeach be substituted by functional groups, aryl, alkyl, aryloxy,alkyloxy, halogen, heteroatoms and/or heterocycles.

Examples of the respective groups have already been given above.

Preferred radicals R^(a), R^(b) and R^(c) are methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl (n-amyl), 2-pentyl(sec-amyl), 3-pentyl, 2,2-dimethylprop-1-yl (neopentyl), n-hexyl,n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, 1,1-dimethylpropyl,1,1-dimethylbutyl, benzyl, 1-phenylethyl, 2-phenylethyl,α,α-dimethylbenzyl, phenyl, tolyl, xylyl, α-naphthyl, β-naphthyl,cyclopentyl and cyclohexyl.

If two of the radicals R^(a), R^(b) and R^(c) form a chain, this can be,for example, 1,4-butylene or 1,5-pentylene.

Examples of tertiary amines of the formula (XI) arediethyl-n-butylamine, diethyl-tert-butylamine, diethyl-n-pentylamine,diethylhexylamine, diethyloctylamine, diethyl(2-ethylhexyl)amine,di-n-propylbutylamine, di-n-propyl-n-pentylamine, di-n-propylhexylamine,di-n-propyloctylamine, di-n-propyl(2-ethylhexyl)amine,diisopropylethylamine, diisopropyl-n-propylamine, diisopropylbutylamine,diisopropylpentylamine, diisopropylhexylamine, diisopropyloctylamine,diisopropyl(2-ethylhexyl)amine, di-n-butylethylamine,di-n-butyl-n-propylamine, di-n-butyl-n-pentylamin, di-n-butylhexylamine,di-n-butyloctylamine, di-n-butyl(2-ethylhexyl)amine,N-n-butylpyrrolidine, N-sec-butylpyrrolidine, N-tert-butylpyrrolidine,N-n-pentylpyrrolidine, N,N-dimethylcyclohexylamine,N,N-diethylcyclohexylamine, N,N-di-n-butylcyclohexylamine,N-n-propylpiperidine, N-isopropylpiperidine, N-n-butylpiperidine,N-sec-butylpiperidine, N-tert-butylpiperidine, N-n-pentylpiperidine,N-n-butylmorpholine, N-sec-butylmorpholine, N-tert-butylmorpholine,N-n-pentylmorpholine, N-benzyl-N-ethylaniline,N-benzyl-N-n-propylaniline, N-benzyl-N-isopropylaniline,N-benzyl-N-n-butylaniline, N,N-dimethyl-p-toluidine,N,N-diethyl-p-toluidine, N,N-di-n-butyl-p-toluidine, diethylbenzylamine,di-n-propylbenzylamine, di-n-butylbenzylamine, diethylphenylamine,di-n-propylphenylamine and di-n-butylphenylamine and also1,5-diazabicyclo[4.3.0]non-5-ene (DBN).

Preferred tertiary amines (XI) are diisopropylethylamine,diethyl-tert-butylamine, diisopropylbutylamine,di-n-butyl-n-pentylamine, N,N-di-n-butylcyclohexylamine and alsotertiary amines derived from pentyl isomers.

Particularly preferred tertiary amines are di-n-butyl-n-pentylamine andtertiary amines derived from pentyl isomers.

A tertiary amine which is likewise preferred and can be used accordingto the present invention but, in contrast to those mentioned above, hasthree identical radicals is triallylamine.

Tertiary amines, preferably amines of the formula (XI), are generallypreferred over heterocyclic compounds, for example compounds of theformulae (Ia) to (Ir), when the basicity of the latter auxiliary basesis not sufficient for the reaction, for example for eliminations.

Acids which can form salts with these bases are, for example, hydroiodicacid (HI), hydrogen fluoride (HF), hydrogen chloride (HCl), nitric acid(HNO₃), nitrous acid (HNO₂), hydrobromic acid (HBr), carbonic acid(H₂CO₃), hydrogencarbonate (HCO₃—), methylcarbonic acid (HO(CO)OCH₃),ethylcarbonic acid (HO(CO)OC₂H₅), n-butylcarbonic acid, sulfuric acid(H₂SO₄), hydrogensulfate (HSO₄ ⁻), methylsulfuric acid (HO(SO₂)OCH₃),ethylsulfuric acid (HO(SO₂)OC₂H₅), phosphoric acid (H₃PO₄),dihydrogenphosphate (H₂PO₄ ⁻), formic acid (HCOOH), acetic acid(CH₃COOH), propionic acid, n-butyric acid and isobutyric acid, pivalicacid, para-toluenesulfonic acid, benzenesulfonic acid, benzoic acid,2,4,6-trimethylbenzoic acid, mandelic acid, methanesulfonic acid,ethanesulfonic acid and trifluoromethanesulfonic acid, preferablyhydrogen chloride, acetic acid, p-toluenesulfonic acid, methanesulfonicacid, 2,4,6-trimethylbenzoic acid and trifluoromethanesulfonic acid,particularly preferably hydrogen chloride.

In a preferred embodiment for separating off Brönsted acids (proticacids), these are separated off without large proportions of Lewisacids, i.e. the molar ratio of Brönsted acids to Lewis acids in theseparated-off salt of the acid with the auxiliary base is greater than4:1, preferably greater than 5:1, particularly preferably greater than7:1, very particularly preferably greater than 9:1 and in particulargreater than 20:1.

Preference is given to auxiliary bases whose salts with acids have amelting point at which no significant decomposition of the desiredproduct occurs, i.e. less than 10 mol % per hour, preferably less than 5mol %/h, particularly preferably less than 2 mol %/h and veryparticularly preferably less than 1 mol %/h, during the process ofseparating off the salt as liquid phase.

The melting point of the salts of the particularly preferred auxiliarybases are generally below 160° C., particularly preferably below 100° C.and very particularly preferably below 80° C.

Among auxiliary bases, very particularly preference is given to thosewhose salts have an E_(T)(30) value of >35, preferably >40, particularlypreferably >42. The E_(T)(30) value is a measure of the polarity and isdescribed by C. Reichardt in Reichardt, Christian Solvent Effects inOrganic Chemistry Weinheim: VCH, 1979. —XI, (Monographs in ModernChemistry; 3), ISBN 3-527-25793-4 page 241.

An especially preferred base which, for example, achieves the object ofthe present invention is 1-methylimidazole. The use of 1-methylimidazoleas base is mentioned in, for example, DE-A 35 02 106, but that documentdoes not recognize its utility as ionic liquid.

In addition, 1-methylimidazole is effective as a nucleophilic catalyst[Julian Chojnowski, Marek Cypryk, Witold Fortuniak, Heteroatom.Chemistry, 1991, 2, 63-70]. Chojnowski et al. have found that, comparedto triethylamine, 1-methylimidazole accelerates the phosphorylation oft-butanol by a factor of 33 and the silylation ofpentamethyldisiloxanole by a factor of 930.

Furthermore, it has been found that the hydrochloride of1-methylimidazole has a melting point of about 75° C. and is essentiallyimmiscible with nonpolar organic products such asdiethoxyphenylphosphine, triethyl phosphite, ethoxydiphenylphosphine,alkyl ketene dimers, alkoxysilanes or esters, or solvents. Thus, incontrast to the polar solvent water, 1-methylimidazole HCl forms twoimmiscible phases even with acetone. 1-Methylimidazole can act both asauxiliary base and nucleophilic catalyst and can be separated fromorganic media as liquid hydrochloride by means of a simple liquid-liquidphase separation.

Instead of 1-methylimidazole, it is also possible to use1-butylimidazole. The hydrochloride of 1-butylimidazole is liquid downto room temperature, so that 1-butylimidazole can be used as auxiliarybase and catalyst for reactions in which substances which decompose attemperatures above room temperature are handled. The acetate and formateof 1-methylimidazole are likewise liquid at room temperature.

Similarly, it is possible to use all derivatives of imidazole whosesalts have an E_(T)(30) of >35, preferably >40, particularlypreferably >42, and have a melting point at which no significantdecomposition of the desired product occurs during the process ofseparating off the salt as a liquid phase. The polar salts of theseimidazoles form, as indicated above, two immiscible phases withrelatively nonpolar organic media.

A further especially preferred base which meets the requirements of thepresent invention is 2-ethylpyridine. The use of various pyridines asauxiliary bases is described in, for example, DE 198 50 624, but itsutility as ionic liquid is not recognized there.

Pyridine itself and derivatives of pyridine are known as nucleophiliccatalysts to those skilled in the art [Jerry March, Advanced OrganicChemistry, 3^(rd) Edition, John Wiley & Sons, New York 1985, p. 294,334, 347].

Furthermore, it has been found that the hydrochloride of 2-ethylpyridinehas a melting point of about 55° C. and is immiscible with nonpolarorganic products (see above) or solvents. 2-Ethylpyridine can thus servesimultaneously as auxiliary base and nucleophilic catalyst and can beseparated off from organic media as liquid hydrochloride by means of asimple liquid-liquid phase separation.

Similarly, it is possible to use all derivatives of pyridine whose saltshave an E_(T)(30) of >35, preferably >40, particularly preferably >42,and have a melting point at which no significant decomposition of thedesired product occurs during the process of separating off the salt asa liquid phase. The polar salts of these pyridines form two immisciblephases with relatively nonpolar organic media.

The way in which the reaction is carried out is not restricted and can,according to the present invention, be carried out batchwise orcontinuously with the acids liberated or added beingneutralized/trapped, in the presence or absence of a nucleophiliccatalyst and in air or under a protective gas atmosphere.

In the case of heat-sensitive desired products, it can be sufficient toallow the salt of auxiliary base and acid to precipitate as a solid saltduring the reaction and to melt it only for the work-up or afterseparating off the main quantity of the desired product in asolid-liquid separation. In this way, the product is thermally stressedto a lesser extent. The invention further provides a process forseparating the above-described auxiliary bases or auxiliary bases whichare used as nucleophilic catalysts from a reaction mixture by admixingthe reaction mixture with at least one mol of acid per mol of auxiliarybase. This makes it possible to separate off such auxiliary bases asionic liquids by means of a liquid-liquid separation.

The salt of the auxiliary base which has been separated off from thedesired product can be treated in a manner known to those skilled in theart to recover the free base and the latter can be returned to theprocess.

This can be achieved, for example, by treating the salt of the auxiliarybase with a strong base, e.g. NaOH, KOH, Ca(OH)₂, milk of lime, Na₂CO₃,NaHCO₃, K₂CO₃ or KHCO₃, if appropriate in a solvent such as water,methanol, ethanol, n-propanol or isopropanol, n-butanol, n-pentanol orbutanol or pentanol isomer mixtures or acetone, to liberate the freebase. The auxiliary base which has been liberated in this way can beseparated off if it forms a separate phase or, if it is miscible withthe salt of the stronger base or the solution of the salt of thestronger base, can be separated off from the mixture by distillation. Ifnecessary, the liberated auxiliary base can also be separated from thesalt of the stronger base or the solution of the salt of the strongerbase by extraction with an extractant. Examples of extractants aresolvents, alcohols or amines.

If necessary, the auxiliary base can be washed with water or aqueousNaCl or Na₂SO₄ solution and subsequently dried, e.g. by removal of anywater present with the aid of an azeotropic distillation using benzene,toluene, xylene, butanol or cyclohexane.

If necessary, the base can be distilled before reuse.

A further possible method of recirculation is to distill the salt of theauxiliary base so as to decompose it thermally into its startingcomponents, i.e. the free base and the trapped acid. The lower-boilingcomponent of the salt is distilled off, while the higher-boilingcomponent remains in the bottoms. The free auxiliary base is either thelow boiler or the high boiler. In this way, for example,1-butylimidazole formate can be separated by distillation into formicacid (top product) and 1-butylimidazole (bottom product), as describedin EP-A 181 078.

A preferred embodiment comprises distilling off the desired product froma reaction mixture in the presence of the protonated form of theauxiliary base and subsequently, after the desired product has beenlargely removed, setting the auxiliary base free by means of a strongbase and subsequently distilling the free auxiliary base. The reactionmixture can be the product of a chemical reaction or a stream from adistillation or rectification, for example an azeotropic mixture whichhas been admixed with an ionic liquid as entrainer.

It is important to rectify the desired product under conditions underwhich the protonated form of the ionic liquid is not significantlyvolatile, for example as a result of thermal dissociation of theprotonated auxiliary base, and to set free and distill the ionic liquidonly after the desired product has been separated off. Such a procedureis also possible when the desired product is not stable in the presenceof the free form of the auxiliary base and is decomposed.

If the boiling point of the desired product is relatively high, so thatit is not possible to find conditions under which the desired productcan be distilled in the presence of the protonated auxiliary base, theseparation can also be carried out in the reverse order by firstlysetting the auxiliary base free by means of a strong base andsubsequently distilling the auxiliary base in the presence of thedesired product and only then distilling the desired product. This isparticularly advantageous when the desired product is not decomposed bythe strong base used.

The same principle can also be employed when the protonated form of theauxiliary base is used as acid catalyst, i.e. instead of an acid such ashydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid,trifluoromethanesulfonic acid, toluenesulfonic acid, acetic acid orformic acid, its salt with an auxiliary base is used as ionic liquid ina reaction. An advantage of this is that the protonated auxiliary baseforms a liquid phase during the reaction. The catalytic effect of theprotonated auxiliary base can be stopped at any time by addition of astrong base.

In a further preferred embodiment, an acid catalyst is neutralized bychemical reaction with an auxiliary base which forms a liquid salt withthe acid catalyst used, so that the catalyst which has been deactivatedin this way can be separated off in a simple liquid-liquid separation.

Of course, the distillation of an ionic liquid can also be carried outin the absence of the desired product, for example by distilling theionic liquid from a phase separation or a liquid-liquid extraction. Inthis case, the ionic liquid, i.e. the auxiliary base in protonated form,can also contain a proportion of desired product or possibly solvent, ingeneral less than 10% by weight in each case, preferably less than 5% byweight each, particularly preferably less than 3% by weight each. Inthis case, desired product and residual solvent can firstly be removedfrom the ionic liquid, for example by vacuum distillation or strippingwith an inert gas such as nitrogen, and the auxiliary base cansubsequently be set free by means of a strong base and purified bydistillation or rectification.

A purified base can then be recirculated to the process at any time.

It can also be advantageous to use the protonated form of the auxiliarybase as solvent for organic reactions. After the reaction products havebeen separated off, the auxiliary base can be recovered by setting itfree by means of a strong base and distilling it and be recirculated, asdescribed above.

Preferred phosphorylations which can be carried out using the process ofthe present invention are reactions in which phosphorus compounds, forexample phosphines, phosphinic esters, phosphinous esters(phosphinites), phosphonic esters, phosphonic halides, phosphonamides,phosphonous esters (phosphonites), phosphonous amides, phosphonoushalides, phosphoric esters, phosphoric diester halides, phosphoricdiester amides, phosphoric ester dihalides, phosphoric ester diamides,phosphorous esters (phosphites), phosphorous diester halides,phosphorous diester amides, phosphorous ester dihalides or phosphorousester diamides, are formed and an acid which forms a salt as describedabove with the auxiliary base is eliminated.

In these formulae, R, R′ and R″ are any radicals, X and X′ are halidesor pseudohalides, for example F, Cl, Br, I, CN, OCN or SCN, orunsubstituted, monosubstituted or disubstituted amino groups and Z isoxygen, sulfur or an unsubstituted or monosubstituted nitrogen atom.

These can be phosphorus compounds which contain one or more, for exampletwo, three or four, preferably two or three, particularly preferablytwo, phosphorus atoms. In such compounds, the phosphorus atoms aretypically joined by a bridge.

Such bridged compounds having two phosphorus atoms can be, for example:

diphosphites(RO)(R′O)P—O-Z-O—P(OR″)(OR′″)  (formula II),diphosphonites(RO)R′P—O-Z-O—PR″(OR′″)  (formula III),diphosphinites(R)(R′)P—O-Z-O—P(R″)(R′″)  (formula IV),phosphite-phosphonites(RO)(R′O)P—O-Z-O—P(OR″)(R′″)  (formula V),phosphite-phosphinites(RO)(R′O)P—O-Z-O—P(R″)(R′″)  (formula VI),phosphonite-phosphinites(R)(R′O)P—O-Z-O—P(R″)(R′″)  (formula VII),Where R, R′, R″ and R′″ can be any organic radicals and Z can be anydivalent bridge.

For example, the organic radicals can each be, independently of oneanother, a linear or branched, substituted or unsubstituted, aromatic oraliphatic radical having up to 20 carbon atoms, e.g. C₁-C₁₈-alkyl,C₂-C₁₈-alkyl which may be interrupted by one or more oxygen and/orsulfur atoms and/or one or more substituted or unsubstituted iminogroups, C₂-C₁₈-alkenyl, C₆-C₁₂-aryl, C₅-C₁₂-cycloalkyl or a five- tosix-membered, oxygen-, nitrogen- and/or sulfur-containing heterocycle,where the radicals mentioned may each be substituted by aryl, alkyl,aryloxy, alkyloxy, heteroatoms and/or heterocycles.

The compounds mentioned can each be symmetrically or unsymmetricallysubstituted. Phosphorus compounds having one phosphorus atom are, forexample, compounds of the formula (VIII)P(X¹R⁷)(X²R⁸)(X³R⁹)  (VIII)whereX¹, X², X³ are each, independently of one another, oxygen, sulfur, NR¹⁰or a single bondR⁷, R⁸, R⁹, R¹⁰ are, independently of one another, identical ordifferent organic radicals.

Phosphorus compounds having two phosphorus atoms are, for example,compounds of the formula (IX)

whereX¹¹, X¹², X¹³, X²¹, X²², X²³ are each, independently of one another,oxygen, sulfur, NR¹⁰ or a single bond,R¹¹, R¹² are, independently of one another, identical or different,individual or bridged organic radicals,R²¹, R²² are, independently of one another, identical or different,individual or bridged organic radicals,Y is a bridging group.

The phosphorus compounds described are suitable, for example, as ligandsfor catalysts for the hydrocyanation of butadiene to give a mixture ofisomeric pentenenitriles. Apart from the hydrocyanation of1,3-butadiene-containing hydrocarbon mixtures, the catalysts aregenerally suitable for all customary hydrocyanation processes.Particular mention may be made of the hydrocyanation of nonactivatedolefins, e.g. of styrene and 3-pentenenitrile. Furthermore, their usefor hydrogenation, hydroformylation, hydrocarboxylation, hydroamidation,hydroesterification and aldol condensation is conceivable.

Such catalysts can have one or more of the phosphorus compounds asligands. In addition to the phosphorus compounds as ligands, thecatalysts can have at least one further ligand selected from amongcyanide, halides, amines, carboxylates, acetylacetone, arylsulfonatesand alkylsulfonates, hydride, CO, olefins, dienes, cycloolefines,nitriles, N-containing heterocycles, aromatics and heteroaromatics,ethers, PF₃ and monodentate, bidentate and polydentate phosphine,phosphinite, phosphonite and phosphite ligands. These further ligandscan likewise be monodentate, bidentate or polydentate and can coordinateto the metal. Further suitable phosphorus-containing ligands are, forexample, the phosphine, phosphinite and phosphite ligands describedabove as prior art.

The metal is preferably a metal of transition group VIII, particularlypreferably cobalt, rhodium, ruthenium, palladium or nickel in anyoxidation state. If the catalysts according to the present invention areused for hydrocyanation, the metal is a metal of transition group VIII,in particular nickel.

If nickel is used, it can be present in various oxidation states, e.g.0, +1, +2, +3. Preference is given to nickel(0) and nickel(+2), inparticular nickel(0).

In the case of hydroformylation catalysts, catalytically active speciesare generally formed under hydroformylation conditions from thecatalysts or catalyst precursors used in each case.

For this purpose, preference is given to using cobalt, ruthenium,rhodium, palladium, platinum, osmium or iridium, in particular cobalt,rhodium and ruthenium, in any oxidation states as metal.

The preparation of these catalyst systems is technically complicated andexpensive. This is particularly true since the catalyst systems aregradually decomposed during use and thus have to be discharged andreplaced by fresh catalyst.

Methods of preparing the phosphorus compounds and the correspondingcatalysts are known per se, for example from U.S. Pat. No. 3,903,120,U.S. Pat. No. 5,523,453, U.S. Pat. No. 5,981,772, U.S. Pat. No.6,127,567, U.S. Pat. No. 5,693,843, U.S. Pat. No. 5,847,191, WO01/14392, WO 99/13983 and WO 99/64155.

To prepare the phosphorus compounds used as ligands in the catalysts, itis possible, for example, firstly to react a dihalophosphorus(III)compound with a monoalcohol to form a diester. If desired, this compoundcan be isolated and/or purified by known methods, e.g. by distillation,prior to being reacted further. This diester is then, for example,reacted with a diol to form the bidentate phosphonite ligand. Ifsymmetrical ligands are to be obtained, two equivalents of the diestercan be reacted in a single-stage reaction with one equivalent of thediol. Otherwise, one equivalent of the diester is firstly reacted withone equivalent of the diol and, after formation of the monocondensationproduct, a second diol is added and reacted further to form thephosphorus compound.

The acid liberated in the reaction can, according to the presentinvention, be neutralized by means of one of the abovementionedauxiliary bases to form a liquid salt, so that the synthesis can beconsiderably simplified.

Organodiphosphonites of the formula III and catalyst systems in whichsuch organodiphosphonites are present are known, for example from WO99/64155. To prepare such organodiphosphonites of the formula III, WO99/64155 describes the reaction of R′PCl₂ with one mol of ROH andsubsequent reaction of the (RO)R′PCl obtained with half a mol, based onone mol of (RO)R′PCl, of a compound HO-Z-OH at from 40 to about 200° C.In this reaction, the elimination of the hydrogen halide in the firststep preferably occurs purely thermally. In addition, both steps shouldbe carried out in the presence of a base.

For the purposes of the present invention, the processes known from theprior art, e.g. that known from WO 99/64155, are carried out analogouslyfor preparing the abovementioned phosphorus compounds, except that,according to the present invention, an auxiliary base as described aboveis used and the liberated acid is separated from the reaction mixture bymeans of the auxiliary base, with the auxiliary base and the acidforming, as mentioned above, a salt which is liquid at temperatures atwhich the phosphorus compound is not significantly decomposed during theprocess of separating off the liquid salt and the salt of the auxiliarybase forming two immiscible liquid phases with the phosphorus compoundor the solution of the phosphorus compound in a suitable solvent.

In general, the phosphorus compounds mentioned can, for example, beprepared as follows:

The starting materials are, if appropriate as solutions, dispersions,suspensions or emulsions in a solvent, mixed with one another in thedesired stoichiometric ratios. It can be useful to divide the startingmaterials into one or more compositions, i.e. separate streams, so thatthe reaction does not take place prior to mixing. The auxiliary basewhich, according to the present invention, forms a liquid salt with theacid can be mixed into one or more of these streams or be introducedinto the reaction as a separate stream in addition to these streams. Itis also possible, although less preferred, to add the auxiliary baseonly after the reaction for the purpose of separating off the acid.

The starting materials or the compositions mentioned are fed into areactor and reacted with one another under reaction conditions whichlead to reaction of the starting materials to form the product. Suchreaction conditions depend on the starting materials used and thedesired products and are indicated in the prior art mentioned in thepresent text.

The reaction can be carried out continuously, semicontinuously orbatchwise. The temperature generally ranges from 40° C. to 200° C.,while the pressure is not critical according to the present inventionand can be subatmospheric, superatmospheric or atmospheric pressure, forexample from 10 mbar to 10 bar, preferably from 20 mbar to 5 bar,particularly preferably from 50 mbar to 2 bar and in particular from 100mbar to 1.5 bar. The residence time of the reaction mixture in thereactor can be from a few seconds to a number of hours and depends onthe reaction temperature and, generally to a lesser extent, on thepressure applied.

In the case of a continuous reaction at a temperature which issufficiently high for the reaction, preference is given to selecting ashort residence time, i.e. from a few seconds to about 2 hours,preferably from 1 second to 2 hours, particularly preferably from 1second to 1 hour, very particularly preferably from 1 second to 30minutes, in particular from 1 second to 15 minutes and most preferablyfrom 1 second to 5 minutes.

In a particularly preferred embodiment, the preparation of thephosphorus compounds, preferably compounds having a plurality ofphosphorus atoms, particularly compounds having 2 or 3 and veryparticularly preferably 2 phosphorus atoms, from the respective startingmaterials is carried out continuously at from 60° C. to 150° C.,preferably at a temperature above the melting point of the salt of therespective auxiliary base with the acid liberated and up to 130° C., ata residence time of less than 1 hour, preferably less than 30 minutes,particularly preferably less than 15 minutes, very particularlypreferably from 1 second to 5 minutes, in particular from 1 second to 1minute and most preferably from 1 to 30 seconds.

In such an embodiment, the replacement of substituents on the phosphorusatoms is suppressed, so that it is possible to prepare compounds havinga plurality of phosphorus atoms, for example compounds of the formula(IX), and phosphorus compounds having mixed substituents, for examplecompounds of the formula (VIII) with different radicals R⁷, R⁸ and/orR⁹, under predominantly kinetic control without the substituents on thephosphorus atom/atoms being exchanged as a result of equilibration.

Good mixing has to be ensured during the reaction, for example bystirring or pumped circulation through static mixers or nozzles.

As reactors, it is possible to use apparatuses known per se to a personskilled in the art, for example one or more cascaded stirred tanks ortube reactors with internal and/or external heating facilities andpreferably jet nozzle reactors or reaction mixing pumps.

The output from the reactor is passed to an apparatus in which phasesformed during the reaction can separate from one another, for example aphase separator or a mixer-settler apparatus. In this apparatus, thephase comprising predominantly ionic liquid is separated from the phasecomprising predominantly the desired reaction product at a temperatureat which the salt of the auxiliary base with the acid is liquid. Ifnecessary, solvent can be added to accelerate phase separation.

The auxiliary base can, as described above, be recovered from the phasecomprising predominantly ionic liquid.

The desired reaction product can be isolated from the phase in which itis present and/or purified by methods known per se, for example bydistillation, rectification, extraction, fractional or simplecrystallization, membrane separation processes, chromatography orcombinations thereof.

The solvents used in the reaction can be the solvents listed above.

The auxiliary base used in the reaction is generally used in astoichiometric amount, based on the amount of acid expected, or a slightexcess, for example from 100 to 200 mol % based on the amount of acidexpected, preferably from 100 to 150 mol % and particularly preferablyfrom 105 to 125 mol %.

The starting materials for preparing the desired phosphorus compoundsare known per se to those skilled in the art or can readily be obtainedby known methods and are mentioned, for example, in the prior artmentioned in the present text. The stoichiometric ratios in which thestarting materials are to be reacted are likewise known or can readilybe deduced.

The starting materials are preferably used as liquids or melts, and forthis purpose may be dissolved or dispersed in a solvent. However, it isof course also possible to use at least some of the starting materialsas solids.

If they are admixed with a solvent, the solvent is generally used insuch an amount that the mixture is liquid, for example as a solution ordispersion. Typical concentrations of the starting materials based onthe total amount of solution or dispersion are from 5 to 95% by weight,preferably from 10 to 90% by weight, particularly preferably from 25 to90% by weight and very particularly preferably from 50 to 90% by weight.

Compounds (VIII) have the formulaP(X¹R⁷)(X²R⁸)(X³R⁹)  (VIII).

For the purposes of the present invention, the compound (VIII) may be asingle compound or a mixture of various compounds of the abovementionedformula.

According to the present invention, X¹, X², X³ are each, independentlyof one another, oxygen, sulfur, NR¹⁰ or a single bond.

R¹⁰ is hydrogen or an organic radical having 1-10 carbon atoms,preferably hydrogen, phenyl or C₁-C₄-alkyl, which for the purposes ofthe present text refers to methyl, ethyl, isopropyl, n-propyl, n-butyl,isobutyl, sec-butyl or tert-butyl.

If all the groups X¹, X² and X³ are single bonds, the compound (VIII) isa phosphine of the formula P(R⁷R⁸R⁹), where R⁷, R⁸ and R⁹ are as definedin the present description.

If two of the groups X¹, X² and X³ are single bonds and one is oxygen,the compound (VIII) is a phosphinite of the formula P(OR⁷)(R⁸)(R⁹) orP(R⁷)(OR⁸)(R⁹) or P(R⁷)(R⁸)(OR⁹) where R⁷, R⁸ and R⁹ are as defined inthe present description.

If one of the groups X¹, X² and X³ is a single bond and two are oxygen,the compound (VIII) is a phosphonite of the formula P(OR⁷)(OR⁸)(R⁹) orP(R⁷)(OR⁸)(OR⁹) or P(OR⁷)(R⁸)(OR⁹) where R⁷, R⁸ and R⁹ are as defined inthe present description.

In a preferred embodiment, all of the groups X¹, X² and X³ are oxygen,so that the compound (VIII) is advantageously a phosphite of the formulaP(OR⁷)(OR⁸)(OR⁹) where R⁷, R⁸ and R⁹ are as defined in the presentdescription.

According to the present invention, R⁷, R⁸, R⁹ are, independently of oneanother, identical or different organic radicals.

R⁷, R⁸ and R⁹ may be, independently of one another, alkyl radicals,advantageously alkyl radicals having from 1 to 10 carbon atoms, e.g.methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl,aryl groups such as phenyl, o-tolyl, m-tolyl, p-tolyl, p-fluorophenyl,1-naphthyl, 2-naphthyl, or hydrocarbyl, advantageously hydrocarbylhaving from 1 to 20 carbon atoms, e.g. 1,1′-biphenol, 1,1′-binaphthol.

The groups R⁷, R⁸ and R⁹ can be joined to one another directly, i.e. notonly via the central phosphorus atom. It is preferred that the groupsR⁷, R⁸ and R⁹ are not joined directly to one another.

In a preferred embodiment, the groups R⁷, R⁸ and R⁹ may be radicalsselected from the group consisting of phenyl, o-tolyl, m-tolyl andp-tolyl.

In a particularly preferred embodiment, not more than two of the groupsR⁷, R⁸ and R⁹ are phenyl groups.

In another preferred embodiment, not more than two of the groups R⁷, R⁸and R⁹ are o-tolyl groups.

As particularly preferred compounds (VIII), it is possible to usecompounds of the formula(o-tolyl-O—)_(w)(m-tolyl-O—)_(x)(p-tolyl-O—)_(y)(phenyl-O—)_(z)Pwhere w, x, y, z are each a natural number,where w+x+y+z=3 andw, z are each less than or equal to 2,e.g. (p-tolyl-O—)(phenyl)₂P, (m-tolyl-O—)(phenyl)₂P,(o-tolyl-O—)(phenyl)₂P, (p-tolyl-O—)₂(phenyl)P, (m-tolyl-O—)₂(phenyl)P,(o-tolyl-O—)₂(phenyl)P, (m-tolyl-O—)(p-tolyl-O—)(phenyl)P,(o-tolyl-O—)(p-tolyl-O—)(phenyl)P, (o-tolyl-O—)(m-tolyl-O—)(phenyl)P,(p-tolyl-O—)₃P, (m-tolyl-O-)(p-tolyl-O—)₂P, (o-tolyl-O—)(p-tolyl-O—)₂P,(m-tolyl-O—)₂(p-tolyl-O—)P, (o-tolyl-O—)₂(p-tolyl-O—)P,(o-tolyl-O—)(m-tolyl-O—)(p-tolyl-O—)P, (m-tolyl-O—)₃P,(o-tolyl-O—)(m-tolyl-O—)₂P(o-tolyl-O—)₂(m-tolyl-O—)P or mixtures of suchcompounds.

Mixtures comprising, for example, (m-tolyl-O—)₃P,(m-tolyl-O—)₂(p-tolyl-O—)P, (m-tolyl-O—)(p-tolyl-O—)₂P and(p-tolyl-O—)₃P can be obtained by reaction of a mixture comprisingm-cresol and p-cresol, in particular in a molar ratio of 2:1, as isobtained in the fractional distillation of petroleum, with a phosphorustrihalide such as phosphorus trichloride.

Such compounds (VIII) and their preparation are known per se.

Compounds (IX) have the formula

whereX¹¹, X¹², X¹³, X²¹, X²², X²³ are each, independently of one another,oxygen, sulfur, NR¹⁰ or a single bond,R¹¹, R¹² are, independently of one another, identical or different,individual or bridged organic radicals,R²¹, R²² are, independently of one another, identical or different,individual or bridged organic radicals,Y is a bridging group.

For the purposes of the present invention, the compound (IX) may be asingle compound or a mixture of various compounds of the abovementionedformula.

In a preferred embodiment, X¹¹, X¹², X¹³, X²¹, X²², X²³ are each oxygen.In such a case, the bridging group Y is joined to phosphite groups.

In another preferred embodiment, X¹¹ and X¹² are oxygen and X¹³ is asingle bond or X¹¹ and X¹³ are oxygen and X¹² is a single bond, so thatthe phosphorus atom surrounded by X¹¹, X¹² and X¹³ is the central atomof a phosphonite. In such a case, X²¹, X²² and X²³ can be oxygen or X²¹and X²² are oxygen and X²³ is a single bond or X²¹ and X²³ are oxygenand X²² is a single bond or X²³ is oxygen and X²¹ and X²² are each asingle bond or X²¹ is oxygen and X²² and X²³ are each a single bond orX²¹, X²² and X²³ are each a single bond, so that the phosphorus atomsurrounded by X²¹, X²² and X²³ is the central atom of a phosphite,phosphonite, phosphinite or phosphine, preferably a phosphonite.

In another preferred embodiment, X¹³ is oxygen and X¹¹ and X¹² are eacha single bond or X¹¹ is oxygen and X¹² and X¹³ are each a single bond,so that the phosphorus atom surrounded by X¹¹, X¹² and X¹³ is thecentral atom of a phosphinite. In such a case, X²¹, X²² and X²³ can beoxygen or X²³ is oxygen and X²⁴ and X²² are each a single bond or X²¹ isoxygen and X²² and X²³ are each a single bond or X²¹, X²² and X²³ areeach a single bond, so that the phosphorus atom surrounded by X²¹, X²²and X²³ is the central atom of a phosphite, phosphinite or phosphine,preferably a phosphinite.

In another preferred embodiment, X¹¹, X¹² and X¹³ are each a singlebond, so that the phosphorus atom surrounded by X¹¹, X¹² and X¹³ is thecentral atom of a phosphine. In such a case, X²¹, X²² and X²³ can beoxygen or X²¹, X²² and X²³ are each a single bond, so that thephosphorus atom surrounded by X²¹, X²² and X²³ is the central atom of aphosphite or phosphine, preferably a phosphine.

The bridging group Y is advantageously an aryl group, preferably onehaving from 6 to 20 carbon atoms in the aromatic system, which may beunsubstituted or substituted, for example by C₁-C₄-alkyl, halogen, suchas fluorine, chlorine, bromine, halogenated alkyl, such astrifluoromethyl, aryl, such as phenyl. Particularly preferred examplesof bridging groups Y are pyrocatechol, bis(phenol) or bis(naphthol).

The radicals R¹¹ and R¹² can be, independently of one another, identicalor different organic radicals. Advantageous radicals R¹¹ and R¹² arearyl radicals, preferably those having from 6 to 10 carbon atoms, whichmay be unsubstituted or monosubstituted or polysubstituted, inparticular by C₁-C₄-alkyl, halogen, such as fluorine, chlorine, bromine,halogenated alkyl, such as trifluoromethyl, aryl, such as phenyl, orunsubstituted aryl groups.

The radicals R²¹ and R²² can be, independently of one another, identicalor different organic radicals. Advantageous radicals R²¹ and R²² arearyl radicals, preferably those having from 6 to 10 carbon atoms, whichmay be unsubstituted or monosubstituted or polysubstituted, inparticular by C₁-C₄-alkyl, halogen, such as fluorine, chlorine, bromine,halogenated alkyl, such as trifluoromethyl, aryl, such as phenyl, orunsubstituted aryl groups.

The radicals R¹¹ and R¹² can be individual or bridged.

The radicals R²¹ and R²² can be individual or bridged.

The radicals R¹¹, R¹², R²¹ and R²² can all be individual, two can bebridged and two individual or all four can be bridged in the mannerdescribed.

The following, particularly preferred embodiments in the stated scopeare expressly incorporated by reference into the present disclosure:

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 3,773,809, in particular those described in column 2, line 23to column 4, line 14 and in the examples, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 6,127,567, in particular the compounds used in column 2, line23 to column 6, line 35, in the formulae I, II, III, IV, V, VI, VII,VIII and IX and in examples 1 to 29, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 6,171,996, in particular the compounds used in column 2, line25 to column 6, line 39, in the formulae I, II, III, IV, V, VI, VII,VIII and IX and in examples 1 to 29, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 6,380,421, in particular the compounds used in column 2, line58 to column 6, line 63, in the formulae I, II and III and in examples 1to 3, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,488,129, in particular the compounds used in column 3, line 4to column 4, line 33, in the formula I and in examples 1 to 49, comeinto consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,856,555, in particular the compounds used in column 2, line13 to column 5, line 30, in the formulae I and II and in examples 1 to4, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in WO99/46044, particularly the compounds used in page 3, line 7 to page 8,line 27, and in particular those in the formulae Ia to Ig and inexamples 1 to 6, come into consideration.

In a particularly preferred embodiment, the compounds of the formulae I,II, III, IV and V mentioned in U.S. Pat. No. 5,723,641 come intoconsideration.

In a particularly preferred embodiment, the compounds of the formulae I,II, III, IV, V, VI and VII mentioned in U.S. Pat. No. 5,512,696, inparticular the compounds used there in examples 1 to 31, come intoconsideration.

In a particularly preferred embodiment, the compounds of the formulae I,II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV and XVmentioned in U.S. Pat. No. 5,821,378, in particular the compounds usedthere in examples 1 to 73, come into consideration.

In a particularly preferred embodiment, the compounds of the formulae I,II, III, IV, V and VI mentioned in U.S. Pat. No. 5,512,695, inparticular the compounds used there in examples 1 to 6, come intoconsideration.

In a particularly preferred embodiment, the compounds of the formulae I,II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII and XIV mentioned inU.S. Pat. No. 5,981,772, in particular the compounds used there inexamples 1 to 66, come into consideration.

In a particularly preferred embodiment, the compounds of the formulae I,II, III, IV, V, VI, VII, VIII, IX and X mentioned in U.S. Pat. No.6,020,516, in particular the compounds used there in examples 1 to 33,come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,959,135 and those used there in examples 1 to 13, come intoconsideration.

In a particularly preferred embodiment, the compounds of the formulae I,II and III mentioned in U.S. Pat. No. 5,847,191 come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,523,453, in particular the compounds shown there in theformulae 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,19, 20 and 21, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in WO01/14392, preferably the compounds shown there in the formulae V, VI,VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XXI, XXII, XXIII,come into consideration.

In a particularly preferred embodiment, the compounds mentioned in WO98/27054 come into consideration.

In a particularly preferred embodiment, the compounds mentioned in WO99/13983, particularly the compounds mentioned on page 5, line 1 to page11, line 45 and in particular those in the formulae Ia to 1 h andexamples 1 to 24, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in WO99/64155, particularly the compounds mentioned on page 4, line 1 to page12, line 7 and in particular those in the formulae Ia to Ic and examples1 to 4, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application DE 10038037 come into consideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application DE 10046025 come into consideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application number DE 10156292.6 filed on Nov. 19, 2001,in particular the compounds mentioned in the submitted text on page 1,lines 6 to 19 and on page 2, line 21 to page 2, line 30, come intoconsideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application number DE 10150281.8 filed on Oct. 12, 2001,in particular the compounds mentioned in the submitted text on page 1,line 36 to page 5, line 45, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application number DE 10150285.0 filed on Oct. 12, 2001,in particular the compounds mentioned in the submitted text on page 1,line 35 to page 5, line 37, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application number DE 10150286.9 filed on Oct. 12, 2001,in particular the compounds mentioned in the submitted text on page 1,line 37 to page 6, line 15, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in theGerman patent application number DE 10148712.6 filed on Oct. 2, 2001, inparticular the compounds mentioned in the submitted text on page 1,lines 6 to 29 and page 2, line 15 to page 4, line 24, come intoconsideration.

Lewis acids are separated off by combining, according to the presentinvention, auxiliary base and Lewis acid to form a complex which, asdescribed above, is liquid at the relevant temperatures and form a phasewhich is immiscible with the desired product.

A known way of separating off, for example, aluminum trichloride is toadd equimolar amounts of phosphoryl chloride (POCl₃) to the product,with the resulting Cl₃PO.AlCl₃ complex precipitating and being able tobe separated off by, for example, filtration (W. T. Dye, J. Am. Chem.Soc., 1948, 70, 2595). Furthermore, it is known from this document thata precisely determined amount of water can be added to the product so asto form the hydrate of aluminum trichloride which can likewise beseparated off from the product by filtration.

According to Gefter, Zh. Obshch. Khim., 1958, 28, 1338, AlCl₃ can alsobe precipitated by formation of a complex with pyridine and be separatedoff in this way.

DE 32 48 483 discloses a process for separating off AlCl₃ with the aidof NaCl.

A disadvantage of these processes is that these complexes arehygroscopic, as solid complexes require a solid-liquid separation and inthis often have unfavorable filtration properties, e.g. lump formation,which makes any subsequent washing difficult.

EP 838 447 describes the formation of liquid clathrates which areinsoluble in the respective Friedel-Crafts product and can be separatedoff, for example, by means of phase separation.

K. R. Seddon, J. Chem. Tech. Biotechnol. 68 (1997) 351, describesprinciples of a method of separating off Lewis acids with the aid ofionic liquids such as 1-butylpyridinium chloride/aluminum(III) chloride,1-butyl-3-methylimidazolium chloride/aluminum(III) chloride. However,these are permanently cationic systems which, in contrast to, forexample, the auxiliary bases (Ia) to (Ir), cannot be used as free,nonionic auxiliary bases.

EP-A1 1 142 898 describes phosphorylations for the preparation ofbiphenyl phosphonites in which phases of eutectic pyridinehydrochloride/pyridine/aluminum chloride mixtures are separated fromproduct-containing solvent phases.

A disadvantage is that the separation of such liquid mixtures from theproduct is not possible without formation of a eutectic.

According to the present invention, the above-described process forseparating Lewis acids from reaction mixtures by means of an auxiliarybase is carried out using an auxiliary base which satisfies thefollowing conditions:

-   b) the auxiliary base and the Lewis acid form a salt which is liquid    at temperatures at which the desired product is not significantly    decomposed during the process of separating off the liquid salt and-   c) the salt of the auxiliary base forms two immiscible liquid phases    with the desired product or the solution of the desired product in a    suitable solvent.

For this purpose, the reaction with the Lewis acid to produce theproduct is generally carried out in the usual way and the auxiliary baseis added to the reaction mixture after the reaction is complete in orderto separate off the Lewis acid. Of course, the reaction mixture can alsobe added to the auxiliary base. The important thing is that the reactionmixture is mixed with the auxiliary base, with auxiliary base and Lewisacid generally forming a complex. It is usual to employ at least onemole of auxiliary base per mole of Lewis acid to be separated off in thereaction mixture, preferably from 1.0 to 1.5 mol/mol, particularlypreferably from 1.0 to 1.3 mol/mol, very particularly preferably from1.0 to 1.3 mol/mol and in particular from 1.0 to 1.25 mol/mol.

After the Lewis acid and auxiliary base have been mixed, the reactionmixture can be immediately worked up further, but it can also continueto be stirred for from a few minutes to a number of hours, preferablyfrom 5 to 120 minutes, particularly preferably from 10 to 60 minutes andvery particularly preferably from 15 to 45 minutes.

During this time, the reaction mixture can advantageously be kept at atemperature at which the complex of auxiliary base and Lewis acid isliquid but no significant decomposition occurs, although the mixture canalso be kept below the melting point of the complex.

The phase separation is carried out under conditions as have beendescribed above. In the case of a complex of, for example, AlCl₃ andN-methylimidazole, the melting point is about 60° C., so that theseparation, e.g. by phase separation, from the desired product can becarried out at relatively low temperatures.

The separation method of the present invention can be used whereverLewis acids have to be separated from a desired product, preferably inFriedel-Crafts alkylations or acylations, phosphorylations orsulfurations of aromatics, particularly preferably in phosphorylationsof aromatics.

Preferred examples of phosphorylations of aromatics are the reactions ofaromatics with phosphoryl halides, for example PCl₃, PCl₅, POCl₃ orPBr₃, in the presence of Lewis acids as catalysts.

Examples of aromatics which can be used are those of the formula (X),

whereZ is a single bond or any divalent bridge andR³¹, R³², R³³, R³⁴, R³⁵ and R³⁶ are each, independently of one anotherhydrogen, C₁-C₁₈-alkyl, C₂-C₁₈-alkyl which may be interrupted by one ormore oxygen and/or sulfur atoms and/or one or more substituted orunsubstituted imino groups, C₁-C₁₈-alkyloxy, C₁-C₁₈-alkyloxycarbonyl,C₆-C₁₂-aryl, C₅-C₁₂-cycloalkyl, a five- to six-membered, oxygen-,nitrogen- and/or sulfur-containing heterocycle or a functional group ortwo of them together form an unsaturated, saturated or aromatic ringwhich may be interrupted by one or more oxygen and/or sulfur atomsand/or one or more substituted or unsubstituted imino groups, where eachof the radicals mentioned may be substituted by functional groups, aryl,alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles.

Functional groups for this purpose are, for example, nitro (—NO₂),nitroso (—NO), carboxyl (—COOH), halogen (—F, —Cl, —Br, —I), amino(—NH₂, —NH(C₁-C₄-alkyl), —N(C₁-C₄-alkyl)₂), carboxamide (—CONH₂,—CONH(C₁-C₄-alkyl), —CON(C₁-C₄-alkyl)₂), nitrile (—CN), thiol (—SH) orthioether functions (—S(C₁-C₄-alkyl)).

Preference is given to the radicals R³¹, R³², R³³, R³⁴, R³⁵ and R³⁶ eachbeing, independently of one another, hydrogen, C₁-C₄-alkyl,C₁-C₄-alkyloxy, C₁-C₄-alkyloxycarbonyl or halogen.

Particular preference is given to the radicals R³¹, R³², R³³, R³⁴, R³⁵and R³⁶ each being, independently of one another, hydrogen, methyl,tert-butyl, ethyl, methoxy, fluorine or chlorine.

Examples of Z are a single bond, methylene, 1,2-ethylene, 1,1-ethylene,1,1-propylene, 2,2-propylene, 1,2-phenylene, 1,4-dimethyl-2,3-phenylene,oxygen (—O—), unsubstituted or monosubstituted nitrogen (—NH— or—N(C₁-C₄-alkyl)-) and sulfur (—S—).

Z is preferably a single bond, oxygen or methylene.

Particularly preferred aromatics are benzene, toluene, o-, m- orp-xylene, 2,4,6-trimethylbenzene, ethylbenzene, 1-ethyl-3-methylbenzene,1-ethyl-4-methylbenzene, isopropylbenzene, 1,3-diisopropylbenzene,tert-butylbenzene, 1,3-di-tert-butylbenzene,1-tert-butyl-3-methylbenzene, 1-tert-butyl-3,5-dimethylbenzene,n-propylbenzene, styrene, indene, fluorene, dimethylaniline,fluorobenzene, chlorobenzene, bromobenzene, 1,2-, 1,3- or1,4-dichlorobenzene, 1,2-, 1,3- or 1,4-difluorobenzene, 1,1′-binaphthyl,2,2′-di(C₁-C₄-alkyl)-1,1′-binaphthyl, in particular2,2′-dimethyl-1,1′-binaphthyl, 2,2′-di(C₁-C₄-alkyloxy)-1,1′-binaphthyl,in particular 2,2′-dimethoxy-1,1′-binaphthyl,3,3′-bis(C₁-C₄-alkyloxycarbonyl)-1,1′-binaphthyl, biphenyl,3,3′,5,5′-tetra(C₁-C₄-alkyl)oxybiphenyl, in particular3,3′,5,5′-tetramethoxybiphenyl, 3,3′,5,5′-tetra(C₁-C₄-alkyl)biphenyl, inparticular 3,3′,5,5′-tetramethylbiphenyl,3,3′-dimethoxy-5,5′-dimethylbiphenyl, naphthalene,2-(C₁-C₄-alkyl)naphthalene, in particular 2-methylnaphthalene,2-(C₁-C₄-alkyloxy)naphthalene, in particular 2-methoxynaphthalene, anddiphenylmethane.

Very particularly preferred aromatics are benzene, toluene, o-, m- orp-xylene, 2,4,6-trimethylbenzene, isopropylbenzene, tert-butylbenzene,fluorobenzene, chlorobenzene, naphthalene and binaphthyl.

Examples of desired products which can be obtained by phosphorylationsor sulfurations of aromatics, Friedel-Crafts alkylations or acylationsare ethylbenzene, acetophenone, 4-methylacetophenone,4-methoxyacetophenone, propiophenone, benzophenone,dichlorophenylphosphine, diphenylchlorophosphine, tosyl chloride, 1,2-,1,3- and 1,4-diethylbenzene, 1,2,3-, 1,2,4- and 1,3,5-triethylbenzene,cumene (isopropylbenzene), tert-butylbenzene, 1,3- and1,4-methylisopropylbenzene, 9,10-dihydroanthracene, indane, cresol,2,6-xylenol, 2-sec-butylphenol, 4-tert-butylphenol, octyiphenol,nonylphenol, dodecylphenol, thymol and 2,6-di-tert-butyl-4-methylphenol.

According to the present invention, the acid is separated off by meansof a nonionic, i.e. uncharged, auxiliary base. The above-describedauxiliary bases of the formula (Ia) to (Ir) are particularly useful forthis purpose.

In a preferred embodiment for separating off Lewis acids, these areseparated off without substantial proportions of Brönsted acids (proticacids), i.e. the molar ratio of Brönsted acids to Lewis acids in theseparated off salt of the acid with the auxiliary base is not more than1:1, preferably not more than 0.75:1, particularly preferably not morethan 0.5:1, very particularly preferably not more than 0.3:1 and inparticular not more than 0.2:1.

In a further preferred embodiment, further phosphorus compounds whichcan be prepared by the process of the present invention areaminodihalophosphines, diaminohalophosphines, triaminophosphines,phosphorous ester diamides, aminophosphines, diaminophosphines,phosphorous ester amide halides and aminophosphine halides.

It is known from WO 98/19985 that the synthesis of aminochlorophosphinescan be carried out by reacting an N—H-acid compound with phosphorustrichloride in an organic solvent in the presence of an auxiliary basewith formation of an insoluble salt. A disadvantage of this method isthat the salt subsequently has to be separated off by filtration.

In Organometallics 2002, 21, 3873, van der Slot et al. describes thesynthesis of aminochlorophosphines, aminophosphines and phosphoramiditesusing triethylamine as auxiliary base.

The insoluble salts formed in the reaction likewise have to be removedby filtration.

WO 02/83695 describes the synthesis of phosphoramidites and their use inthe hydroformylation of terminal and internal olefins.

The process of the present invention enables phosphorus halides andchelating phosphoramidite ligands to be handled more simply inengineering terms (no removal of the solid salts of the auxiliary base)and enables them to be prepared with high selectivity in a higherspace-time yield in the reaction.

Aminodihalophosphines[N]PXX′Diaminohalophosphines[N][N′]PXTriaminophosphines[N][N′][N″]PPhosphorous ester diamides(RO)P[N][N′]AminophosphinesR′R″P[N]DiaminophosphinesR′P[N][N′]Phosphorous ester amide halides(RO)[N]PXAminophosphine halides[N]R′PX

In these, R, R′ and R″ are any organic radicals which may be identicalor different, X and X′ are halogens or pseudohalogens, for example F,Cl, Br, I, CN, OCN or SCN, preferably Cl, which may be identical ordifferent, and [N], [N′] and [N′] are unsubstituted, monosubstituted ordisubstituted amino groups which may be identical or different.

The compounds prepared can be phosphorus compounds having one or more,for example, two, three or four, preferably two or three andparticularly preferably two, phosphorus atoms. The phosphorus atoms insuch compounds are typically linked by a bridge.

For example, such bridged compounds having two phosphorus atoms can be:

systems which are both nitrogen- and oxygen-substituted on eachphosphorus:

diphosphorous diester amides[N](R′O)P—O-Z-O—P[N′](OR″)systems which are nitrogen-substituted on each phosphorus:diphosphorous ester diamides[N][N′]P—O-Z-O—P[N″][N′″]bistriaminophosphines[N][N]P—[N″]-Z-[N′″]—P[N″″][N′″″]unsymmetrically substituted systems:[N](R′O)P—O-Z-O—P(OR″)(OR′″)[N][N′]P—O-Z-O—P(OR″)(OR′″)[N][N′]P—O-Z-O—P[N″](OR′″)systems which are both nitrogen- and carbon-substituted on eachphosphorus:[N](R′)P—O-Z-O—P[N′](R′″)[N](R′)P—[N″]-Z-[N′″]P[N′](R′″)unsymmetrical systems:[N](R′O)P—O-Z-O—P[N](R′″)

In these, R, R′, R″ and R′″ can be any organic radicals which may beidentical or different, [N], [N′], [N″], [N′″], [N″″] and [N′″″] areunsubstituted, monosubstituted or disubstituted amino groups which maybe identical or different and Z can be any divalent bridge.

Of course, other permutations which are not explicitly mentioned hereare also conceivable.

R, R′, R″ and R′″ can, for example, each be, independently of oneanother, a linear or branched, substituted or unsubstituted, aromatic oraliphatic radical having from one to 20 carbon atoms, e.g. C₁-C₁₈-alkyl,C₂-C₁₈-alkyl which may be interrupted by one or more oxygen and/orsulfur atoms and/or one or more substituted or unsubstituted iminogroups, C₂-C₁₈-alkenyl, C₆-C₁₂-aryl, C₅-C₁₂-cycloalkyl or a five- tosix-membered, oxygen-, nitrogen- and/or sulfur-containing heterocycle,where each of the radicals mentioned may be substituted by aryl, alkyl,aryloxy, alkyloxy, heteroatoms and/or heterocycles.

The divalent bridge Z can be, for example, unsubstituted or halogen-,C₁-C₈-alkyl-, C₂-C₈-alkenyl-, carboxy-, carboxy-C₁-C₈-alkyl-,C₁-C₂₀-acyl-, C₁-C₈-alkoxy-, C₆-C₁₂-aryl-, hydroxyl- orhydroxy-C₁-C₈-alkyl-substituted C₆-C₁₂-arylene, C₃-C₁₂-cycloalkylene,C₁-C₂₀-alkylene or C₂-C₂₀-alkylene interrupted by one or more oxygenand/or sulfur atoms and/or one or more substituted or unsubstitutedimino groups and/or by one or more —(CO)—, —O(CO)O—, —(NH)(CO)O—,—O(CO)(NH)—, —O(CO)— or —(CO)O— groups.

Preference is given to divalent bridges Z of the formula (XII),

and those of the formulae (XIII.a) to (XIII.t)

where

A¹ and A² are each, independently of one another, O, S, SiR⁵¹R⁵², NR⁵³or CR⁵⁴R⁵⁵, where

R⁵¹, R⁵² and R⁵³ are each, independently of one another, hydrogen,alkyl, cycloalkyl, heterocycloalkyl, aryl or hetaryl,

R⁵⁴ and R⁵⁵ are each, independently of one another, hydrogen, alkyl,cycloalkyl, heterocycloalkyl, aryl or hetaryl or the group R⁵⁴ togetherwith a further group R⁵⁴ or the group R⁵⁵ together with a further groupR⁵⁵ forms an intramolecular bridging group D,

where A¹ in the formulae XIII.a to XIII.t may also be a C₂- orC₃-alkylene bridge which may contain a double bond and/or bear an alkyl,cycloalkyl, heterocycloalkyl, aryl or hetaryl substituent or beinterrupted by O, S, SiR⁵¹R⁵² or NR⁵³,

D is a divalent bridging group selected from among the groups

whereR⁶¹ and R⁶² are each, independently of one another, hydrogen, alkyl,cycloalkyl, aryl, halogen, trifluoromethyl, carboxyl, carboxylate orcyano or are joined to one another to form a C₃-C₄-alkylene bridge,R⁶³, R⁶⁴, R⁶⁵ and R⁶⁶ are each, independently of one another, hydrogen,alkyl, cycloalkyl, aryl, halogen, trifluoromethyl, COOH, carboxylate,cyano, alkoxy, SO₃H, sulfonate, NE¹E², alkylene-NE¹E²E³⁺X⁻, acyl ornitro,c is 0 or 1,where in the case of c being 0, the groups A¹ and A² are not joined toone another by a single bond,R^(I), R^(II), R^(III), R^(IV), R^(V), R^(VI), R^(VII), R^(VIII),R^(IX), R^(X), R^(XI) and R^(XII) are each, independently of oneanother, hydrogen, alkyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl,hetaryl, halogen, COOR⁵⁶, COO⁻M⁺, SO₃R⁵⁶, SO⁻ ₃M⁺, NE¹E², NE¹E²E³⁺,alkylene-NE¹E², alkylene NE¹E²E³⁺X⁻, OR⁵⁶, SR⁵⁶, (CHR⁵⁷CH₂O)_(w)R⁵⁶,(CH₂N(E¹))_(w)R⁵⁶, (CH₂CH₂N(E¹))_(w)R⁵⁶, halogen, trifluoromethyl,nitro, acyl or cyano,whereR⁵⁶, E¹, E² and E³ are identical or different radicals selected fromamong hydrogen, alkyl, cycloalkyl and aryl,R⁵⁷ is hydrogen, methyl or ethyl,M⁺ is a cation,X⁻ is an anion, andw is an integer from 1 to 120,ortwo adjacent radicals selected from among R^(I), R^(II), R^(III),R^(IV), R^(V), R^(VI), R^(VII) and R^(VIII) together with two adjacentcarbon atoms of the benzene ring to which they are bound form a fusedring system having 1, 2 or 3 further rings.

Preferred bridging groups Z of the formula (XII) are ones in which theindex c is 0 and the groups A¹ and A² are selected from among the groupsO, S and CR^(d)R^(e), in particular from among O, S, the methylene group(R⁵⁴═R⁵⁵═H), the dimethylmethylene group (R⁵⁴═R⁵⁵═CH₃), thediethylmethylene group (R⁵⁴═R⁵⁵═C₂H₅), the di-n-propylmethylene group(R⁵⁴═R⁵⁵═n-propyl) and the di-n-butyl-methylene group (R⁵⁴═R⁵⁵=n-butyl).Particular preference is given to bridging groups Z in which A¹ isdifferent from A² and A¹ is preferably a CR^(d)R^(e) group and A² ispreferably an O or S group, particularly preferably an oxa group O.

Particularly preferred bridging groups Z are thus those which are madeup of a triptycene-like or xanthene-like (A¹: CR^(d)R^(e), A²: O)framework.

The substituents R^(I), R^(II), R^(III), R^(IV), R^(V), R^(VI), R^(VII),R^(VIII), R^(IX), R^(X), R^(XI) and R^(XII) are preferably selected fromamong hydrogen, alkyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl andhetaryl. In a first preferred embodiment, R^(I), R^(II), R^(III),R^(IV), R^(V), R^(VI), R^(VII), R^(VIII), R^(IX), R^(X), R^(XI) andR^(XII) are each hydrogen. In a further preferred embodiment, R^(I) andR^(VI) in XIII.p and XIII.q. are each, independently of one another,C₁-C₄-alkyl or C₁-C₄-alkoxy. R^(I) and R^(VI) are preferably selectedfrom among methyl, ethyl, isopropyl, tert-butyl and methoxy. In thesecompounds, R^(II), R^(III), R^(IV) and R^(V) are preferably eachhydrogen.

In a further preferred embodiment, R^(I), R^(III), R^(VI) and R^(VIII)in XIII.b, XIII.c and XIII.f are each, independently of one another,C₁-C₄-alkyl or C₁-C₄-alkoxy. R^(I), R^(III), R^(VI) and R^(VIII) arepreferably selected from among methyl, ethyl, isopropyl, tert-butyl andmethoxy. In these compounds, R^(II), R^(IV), R^(V) and R^(VII) arepreferably each hydrogen.

In a further preferred embodiment, R^(I), R^(III), R^(IV), R^(V), R^(VI)and R^(VIII) in XIII.b, XIII.c and XIII.f are each, independently of oneanother, C₁-C₄-alkyl or C₁-C₄-alkoxy. R^(I), R^(III), R^(IV), R^(V),R^(VI) and R^(VIII) are preferably selected from among methyl, ethyl,isopropyl, tert-butyl and methoxy. In these compounds, R^(II) andR^(VII) are preferably each hydrogen.

In a further preferred embodiment, R^(I) and R^(XII) in XIII.d andXIII.e are each, independently of one another, C₁-C₄-alkyl,C₁-C₄-alkoxy, C₁-C₄-carboalkoxy or C₁-C₄-trialkylsilyl. R^(I) andR^(XII) are preferably selected from among methyl, ethyl, isopropyl,tert-butyl, methoxy, carbomethoxy and trimethylsilyl. In thesecompounds, R^(II), R^(III), R^(IV), R^(V), R^(VI), R^(VII), R^(VIII),R^(IX), R^(X) and R^(XI) are preferably each hydrogen.

When two adjacent radicals selected from among R^(I), R^(II), R^(III),R^(IV), R^(V), R^(VI), R^(VII), R^(VIII), R^(IX), R^(X), R^(XI) andR^(XII) form a fused-on ring system, the ring system is preferably abenzene or naphthalene unit. Fused-on benzene rings are preferablyunsubstituted or bear 1, 2 or 3, in particular 1 or 2, substituentsselected from among alkyl, alkoxy, halogen, SO₃H, sulfonate, NE¹E²,alkylene-NE¹E², trifluoromethyl, nitro, COOR^(f), alkoxycarbonyl, acyland cyano. Fused-on naphthalene units are preferably unsubstituted orhave a total of 1, 2 or 3, in particular 1 or 2, of the substituentsmentioned above in respect of the fused-on benzene rings in the ringwhich is not fused on and/or in the fused-on ring.

Among the groups XIII.a to XIII.t, preference is given to the groupsXIII.a to XIII.e and particular preference is given to the groups XIII.band XIII.d.

The unsubstituted, monosubstituted or disubstituted amino groups [N],[N′], [N″], [N′″], [N″″] and [N′″″] can each be, independently of oneanother, an —NR⁴¹R⁴² group, where

R⁴¹ and R⁴² are each, independently of one another, C₁-C₁₈-alkyl,C₂-C₁₈-alkyl which may be interrupted by one or more oxygen and/orsulfur atoms and/or one or more substituted or unsubstituted aminogroups, C₂-C₁₈-alkenyl, C₆-C₁₂-aryl, C₅-C₁₂-cycloalkyl or a five- orsix-membered, oxygen-, nitrogen- and/or sulfur-containing heterocycle,where each of the radicals mentioned may be substituted by aryl, alkyl,aryloxy, alkyloxy, heteroatoms and/or heterocycles and R⁴¹ and R⁴² maytogether also form a ring.

Preferred group —NR⁴¹R⁴² in which R⁴¹ and R⁴² form a ring are groups ofthe formulae XIV.a to XIV.k

whereAlk is a C₁-C₄-alkyl group andR^(o), R^(p), R^(q) and R^(r) are each, independently of one another,hydrogen, C₁-C₄-alkyl, C₁-C₄-alkoxy, acyl, halogen, trifluoromethyl,C₁-C₄-alkoxycarbonyl or carboxyl.

For the purposes of illustration, some advantageous pyrrole groups arelisted below:

The 3-methylindolyl group (skatolyl group) of the formula XIV.f1 isparticularly advantageous.

It can also be advantageous for two groups [N] and [N′] or [N″] and[N′″], for example pyrroles or indoles, bound to a phosphorus atom to bebound to one another via bridges A³ in positions 2 or 3,

whereA³ is a single bond, O, S, SiR⁵¹R⁵², NR⁵³, CR⁵⁴R⁵⁵ or a C₂- orC₁₀-alkylene bridge which may have a double bond and/or bear an alkyl,cycloalkyl, heterocycloalkyl, aryl or hetaryl substituent or beinterrupted by O, S, SiR⁵¹R⁵² or NR⁵³, where R⁵¹, R⁵², R⁵³, R⁵⁴ and R⁵⁵are as defined above, andR⁷¹, R⁷², R⁷³, R⁷⁴, R⁷⁵ and R⁷⁶ are each, independently of one another,hydrogen, alkyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl, hetaryl,halogen, COOR⁵⁶, COO⁻M⁺, SO₃R⁵⁶, SO⁻ ₃M⁺, NE¹E², NE¹E²E³⁺X⁻,alkylene-NE¹E², alkylene-NE¹E²E³⁺X⁻, OR⁵⁶, SR⁵⁶, (CHR⁵⁷CH₂O)_(w)R⁵⁶,(CH₂N(E¹))_(w)R⁵⁶, (CH₂CH₂N(E¹))_(w)R⁵⁶, halogen, trifluoromethyl,nitro, acyl or cyano, where R⁵⁶, E¹, E², E³ and X are as defined above.

The groups R⁷¹ and R⁷² and/or R⁷⁵ and R⁷⁶ can also together form afive-, six- or seven-membered ring by together forming a chain which maybe substituted by alkyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl,hetaryl or halogen and has three, four or five carbon atoms in thechain, for example 1,3-propylene, 1,4-butylene, 1,5-pentylene andpreferably 1,4-buta-1,3-dienylene.

The compounds mentioned can in each case be symmetrically orunsymmetrically substituted.

The phosphorus compounds described are, for example, suitable as ligandsfor catalysts for the hydroformylation of terminal and internal olefins.Their use for hydrocyanation, hydrogenation, hydrocarboxylation,hydroamidation, hydroesterification and aldol condensation is alsoconceivable.

Such catalysts can have one or more phosphorus compounds as ligands. Inaddition to the phosphorus compounds as ligands, they can furthercomprise at least one additional ligand selected from among hydride,alkyl, cyanide, halides, amines, carboxylates, acetylacetone,arylsulfonates and alkylsulfonates, hydride, CO, olefins, dienes,cycloolefins, nitrites, N-containing heterocycles, aromatics andheteroaromatics, ethers, PF₃ and monodentate, bidentate and polydentatephosphine, phosphinite, phosphonite and phosphite ligands. These furtherligands can likewise be monodentate, bidentate or polydentate andcoordinate to the metal. Suitable further phosphorus-containing ligandsare, for example, the phosphine, phosphinite and phosphite ligandsdescribed previously as prior art.

The metal is preferably a metal of transition group VIII, particularlypreferably cobalt, rhodium, ruthenium, palladium or nickel atoms in anyoxidation state. If the catalysts prepared according to the presentinvention are used for hydroformylation, the metal of transition groupVIII is most preferably rhodium.

In the case of hydroformylation catalysts, catalytically active speciesare generally formed under hydroformylation conditions from thecatalysts or catalyst precursors used.

In such a case, the metal used is preferably cobalt, ruthenium, rhodium,palladium, platinum, osmium or iridium, in particular cobalt, rhodium orruthenium, in any oxidation state.

Methods of preparing the phosphorus compounds and the correspondingcatalysts are known per se, for example from U.S. Pat. No. 3,903,120,U.S. Pat. No. 5,523,453, U.S. Pat. No. 5,981,772, U.S. Pat. No.6,127,567, U.S. Pat. No. 5,693,843, U.S. Pat. No. 5,847,191, WO01/14392, WO 99/13983 and WO 99/64155.

To prepare the phosphorus compounds used as ligands in the catalysts, itis possible, for example, to react phosphorus trichloride with twoequivalents of a pyrrole-type compound, forming adiaminochlorophosphine. To synthesize diphosphoramidites, thediaminochlorophosphine prepared according to the present invention (orelse conventionally) can be reacted with a diol to give a bidentateligand. If unsymmetrical ligands are to be prepared, one equivalent ofthe, for example, diaminochlorophosphine is firstly reacted with thediol, and the further coupling component (e.g. an aryidichlorophosphine)is subsequently added.

The starting materials are mixed with one another in amountscorresponding to the desired stoichiometry, if desired dissolved ordispersed, i.e. suspended or emulsified, in a solvent. It can be usefulto divide up the starting materials into one or more compositions, i.e.separate streams, so that the reaction does not take place beforemixing. The auxiliary base which, according to the present invention,forms a liquid salt with the acid can be mixed into one or more of thesestreams or be introduced into the reaction as an individual streamseparate from the other streams. It is also possible, although lesspreferred, to add the auxiliary base only after the reaction in order toseparate off the acid.

The starting materials or the compositions mentioned are fed into areactor and reacted with one another under reaction conditions whichlead to reaction of the starting materials to form the product. Suchreaction conditions depend on the starting materials used and thedesired products and are described in the prior art cited in this text.

The reaction can be carried out continuously, semicontinuously orbatchwise. The temperature is generally in the range from 30° C. to 190°C., preferably from 70 to 120° C. The pressure is not critical accordingto the present invention and can be subatmospheric, superatmospheric oratmospheric pressure, for example from 10 mbar to 10 bar, preferablyfrom 20 mbar to 5 bar, particularly preferably from 50 mbar to 2 bar andin particular from 100 mbar to 1.5 bar. The residence time of thereaction mixture in the reactor can be from a few seconds to a number ofhours and is dependent on the reaction temperature and, generally to alesser extent, on the pressure applied.

In the case of a continuous reaction at a temperature which issufficiently high for the reaction, for example from 30° C. to 190° C.,preferably from 70 to 120° C., the residence time is preferably short,i.e. from a few seconds to about 2 hours, preferably from 1 second to 2hours, particularly preferably from 1 second to 1 hour, veryparticularly preferably from 1 second to 30 minutes, in particular from1 second to 15 minutes and especially preferably from 1 second to 5minutes.

In a particularly preferred embodiment, the preparation of thephosphorus compounds, preferably phosphorus compounds having a pluralityof phosphorus atoms, particularly preferably compounds having 2 or 3 andvery particularly preferably 2 phosphorus atoms, from the respectivestarting materials is carried out continuously at from 60° C. to 150°C., preferably at a temperature above the melting point of the salt ofthe auxiliary base used with the acid liberated up to 130° C. at aresidence time of less than 1 hour, preferably less than 30 minutes,particularly preferably less than 15 minutes, very particularlypreferably from 1 second to 5 minutes, in particular from 1 second to 1minute and especially preferably from 1 to 30 seconds.

In such an embodiment, the replacement of substituents on the phosphorusatoms can be suppressed, and it thus becomes possible to preparecompounds having a plurality of phosphorus atoms and phosphoruscompounds having mixed substituents under predominantly kinetic controlwithout the substituents on the phosphorus atom or atoms being exchangedas a result of equilibration.

Good mixing has to be ensured during the reaction, for example bystirring or pumped circulation using static mixers or nozzles.

As reactors, it is possible to use apparatuses known per se to thoseskilled in the art, for example one or more cascaded stirred or tubereactors having internal or external heating and preferably jet nozzlereactors or reaction mixing pumps.

The output from the reaction is passed to an apparatus in which phasesformed during the reaction can separate, for example phase separators ormixer-settler apparatuses. In this apparatus, the phase comprisingpredominantly ionic liquid is separated from the phase comprisingpredominantly the desired reaction product at a temperature at which thesalt of the auxiliary base with the acid is liquid. If necessary,solvents can be added to accelerate phase separation.

The auxiliary base can be recovered from the phase comprisingpredominantly ionic liquid in the manner described above.

The reaction product can be isolated from the phase comprising thedesired reaction product and/or be purified using methods known per se,for example by distillation, rectification, extraction, fractional orsimple crystallization, membrane separation processes, chromatography orcombinations thereof.

The solvent used in the reaction can be one of the solvents mentionedabove.

The auxiliary base employed in the reaction is generally used in astoichiometric amount or slight excess, based on the expected amount ofacid, for example in an amount of from 100 to 200 mol % based on theexpected amount of acid, preferably from 100 to 150 mol % andparticularly preferably from 105 to 125 mol %. If the auxiliary baseadded serves as solubilizer, it is also possible to use larger amountsof auxiliary base, for example up to 1000 mol % or more.

The starting materials for preparing the desired phosphorus compoundsare known per se to those skilled in the art or can easily be found andare reported, for example, in the prior art cited in this text. The sameapplies to the stoichiometric ratios in which the starting materialsshould be reacted.

The starting materials are if possible used as liquids or melts; ifappropriate, they are dissolved or dispersed in a solvent for thispurpose. However, it is of course also possible to use at least some ofthe starting materials as solids.

If they are admixed with a solvent, the solvent is generally used insuch an amount that the mixture is liquid, for example as a solution ordispersion. Typical concentrations of the starting materials based onthe total amount of the solution or dispersion are from 5 to 95% byweight, preferably from 10 to 90% by weight.

The acid liberated in the reaction can, according to the presentinvention, be neutralized with one of the auxiliary bases mentioned toform a liquid salt, so that the synthesis can be considerablysimplified.

Preference is given to the preparation according to the presentinvention of phosphorous ester diamides of the formula (RO)P[N][N′],where R, [N] and [N′] are as defined above.

Particular preference is given to the preparation according to thepresent invention of diphosphorous ester diamides of the formula[N][N′]P—O-Z-O—P[N″][N′″], where Z, [N], [N′], [N″] and [N′″] are asdefined above.

Especial preference is given to the preparation according to the presentinvention of the following compounds:

The following, particularly preferred embodiments in the stated scopeare expressly incorporated by reference into the present disclosure:

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 4,668,651, in particular the compounds described in column 9,line 25 to column 16, line 53 and in examples 1 to 11, and also ligandsA to Q, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 4,748,261, in particular the compounds described in column 14,line 26 to column 62, line 48 and in examples 1 to 14, and also ligands1 to 8, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 4,769,498, in particular the compounds described in column 9,line 27 to column 18, line 14 and in examples 1 to 14, and also ligandsA to Q, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 4,885,401, in particular the compounds described in column 12,line 43 to column 30 inclusive and in examples 1 to 14, and also ligands1 to 8, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,235,113, in particular the compounds described in column 7 tocolumn 40, line 11 and in examples 1 to 22, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,391,801, in particular the compounds described in column 7 tocolumn 40, line 38 and in examples 1 to 22, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,663,403, in particular the compounds described in column 5,line 23 to column 26, line 33 and in examples 1 to 13, come intoconsideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 5,728,861, in particular the compounds described in column 5,line 23 to column 26, line 23 and in examples 1 to 13, and also ligands1 to 11, come into consideration.

In a particularly preferred embodiment, the compounds mentioned in U.S.Pat. No. 6,172,267, in particular the compounds described in column 11to column 40, line 48 and in examples 1 and 2, and also ligands 1 to 11,come into consideration.

In a particularly preferred embodiment, the compounds mentioned inJP2002-47294 come into consideration.

ppm figures and percentages used in the present text are by weightunless indicated otherwise.

EXAMPLES Comparative Example 1 Preparation of Diethoxyphenylphosphine(DEOPP)

101.4 g of ethanol, 543 g of xylene and 232.7 g of triethylamine wereplaced in a 1000 ml reactor which was fitted with an impeller stirrerand had been made inert with N₂, and the mixture was heated to 50° C.181.5 g of 98.6% strength dichlorophenylphopshine was added dropwise tothis mixture over a period of 40 minutes, resulting in formation of acolorless, readily stirrable suspension. The reaction temperature wasmaintained at 50° C. by cooling. After all the dichlorophenylphosphinehad been added, the mixture was stirred at 75-80° C. for another 60minutes and the precipitated hydrochloride was subsequently filtered offwith suction and washed with cold xylene. Filtrate and xylene washingswere combined (total: 859.9 g) and analyzed by means of GC using aninternal standard. The xylene solution contained 11.8% ofdiethoxyphenylphosphine, corresponding to a yield of 51%.

Comparative Example 2 Preparation of Diethoxyphenylphosphine (DEOPP)

90.9 g of ethanol and 382.2 g of tributylamine were placed in a 1000 mlreactor which was fitted with an impeller stirrer and had been madeinert with N₂, and the mixture was heated to 70° C. 162.7 g of 98.6%strength dichlorophenylphopshine was added dropwise to this mixture overa period of 40 minutes, resulting in formation of a colorless solutionwhich was liquid when hot and solidified after cooling to roomtemperature to give a colorless, crystalline solid. The reactiontemperature was maintained at 50° C. by cooling. After all thedichlorophenylphosphine had been added, the mixture was stirred at75-80° C. for another 60 minutes. According to GC using an internalstandard, the 625.8 g of reaction product contained 23.7% ofdiethoxyphenylphosphine, corresponding to a yield of 82.7%.

Example 1 Preparation of Diethoxyphenylphosphine (DEOPP)

188.9 g (2.3 mol) of 1-methylimidazole and 101.4 g (2.2 mol) of ethanolwere placed in a 1000 ml reactor which was fitted with an inclined-bladestirrer and had been made inert with N₂. 181.5 g (1.0 mol) of 98.6%strength dichlorophenylphosphine were then introduced over a period of90 minutes. Initially, spontaneous heating to 60° C. was permitted(duration: 6 min) and the temperature was subsequently maintained at 60°C. by cooling during the further addition. After the addition wascomplete, the mixture was still liquid, but crystallized during thefurther stirring time of 45 minutes. After heating to 80° C., thereaction mixture was completely liquid again. After stirring for afurther one hour, the stirrer was switched off. Two well-definedseparate phases were quickly formed. Phase separation at 80° C. gave199.4 g of a clear, colorless upper phase (DEOPP content according toGC: 96.1%; 1-methylimidazole content: 1.7%) and 266.4 g of a lower phase(“ionic liquid”).

The upper phase was distilled under reduced pressure via a 40 cm columnprovided with 5 mm Raschig rings. This gave 15.8 g of a clear, colorlessfirst fraction (GC:DEOPP content=76.9%) and 177.5 g of a colorless mainfraction (GC:DEOPP content=99.4%). Only 4.3 g of bottoms which accordingto GC still contained 11.1% of DEOPP remained in the flask. The DEOPPyield after distillation was 95.9%.

Example 2 Preparation of Triethyl Phosphite (TEP)

425 g of 1-methylimidazole and 228.1 g of ethanol were placed in a 1000ml reactor which was equipped with an inclined-blade stirrer and hadbeen made inert with N₂. While cooling in ice, 206 g of phosphorustrichloride were then added dropwise at an internal temperature of23-33° C. over a period of 190 minutes. The reaction proceededexothermically, so that cooling had to be employed to maintain thistemperature. After about half of the phosphorus trichloride had beenadded, the reaction mixture became turbid and two liquid phases wereobtained. The upper phase contained 90.0% of triethyl phosphiteaccording to GC, and the lower phase comprised the hydrochloride of1-methylimidazole. Before phase separation, the mixture was heated to78° C. 231.4 g of a colorless upper phase and 611.9 g of a clear lowerphase were obtained. The upper phase was distilled under reducedpressure via a 30 cm glass column containing Sulzer DX packing. Thisgave 177 g of triethyl phosphite having a purity of 99%. A further 28.3g of triethyl phosphite were present in the first fraction and the thirdfraction. The total yield was 82.4%.

Example 3 Preparation of Diethoxyphenylphosphine (DEOPP)

85.7 g of 2-methylpyridine and 40.5 g of ethanol were placed in a 250 mlglass flask fitted with a Teflon blade stirrer. While cooling, 71.6 g ofdichlorophenylphosphine (98.6% strength) were added dropwise over aperiod of 25 minutes at such a rate that the internal temperatureremained at 20-29° C. The hydrochloride of 2-methylpyridine precipitatedduring the addition. After the addition was complete, the mixture washeated, and the hydrochloride began to melt above about 70° C. Twoclear, sharply defined liquid phases were formed, viz. 75.5 g of anupper phase and 115.8 g of a lower phase. The upper phase contained 81.6g of DEOPP, so that the yield was 77.7%.

When the lower phase was neutralized with aqueous sodium hydroxidesolution, a two-phase system was reformed, with the lower phaseconsisting of an aqueous sodium chloride solution and the upper phasecomprising the free 2-methylpyridine which could in this way berecirculated via a simple liquid-liquid phase separation.

Example 4 Preparation of Ethoxydiphenylphosphine (EODPP)

141.7 g of 1-methylimidazole and 76.0 g of ethanol were placed in a 1000ml reactor which was equipped with an inclined-blade stirrer and hadbeen made inert with N₂, and 315.8 g of chlorodiphenylphosphine wereadded dropwise over a period of 30 minutes, resulting in formation oftwo liquid phases. The internal temperature was kept below 65° C. Afterthe addition was complete, the mixture was heated to 75° C., stirred for45 min and the phases were separated, giving 194.3 g of a lower phaseand 332.8 g of an upper phase. According to GC, the upper phasecomprised 96.6% of the product EODPP. To purify the product further, theupper phase was distilled under reduced pressure via a glass columnprovided with Raschig rings, giving 292.5 g of 99.4% strength EODPP.Together with the EODPP in the first fraction, the total yield was92.2%.

The lower phase, which comprised the liquid hydrochloride of1-methylimidazole, was admixed with 244.1 g of 25% strength aqueoussodium hydroxide solution. To dissolve the precipitated sodium chloridecompletely, a further 94.3 g of water were added until a clear solutionwas obtained. After addition of 450 g of n-propanol, further sodiumchloride precipitated and this was brought back into solution by afurther addition of 69.8 g of water. The result was two liquid phases,with the 739.3 g of upper phase containing 19.99% of water and 16.7% of1-methylimidazole. This corresponds to 94.9% of the amount of1-methylimidazole used in the synthesis. The 304.2 g of lower phasecontained the sodium chloride together with 70.6% of water and 2.2% of1-methylimidazole. The 1-methylimidazole content of the aqueous phasecould be reduced to 0.4% by extracting it again with n-propanol.1-Methylimidazole could then be recovered by the mixture of propanol andwater being distilled off from the upper phase of the first extraction.

Example 5 Continuous Preparation of Ethoxydiphenylphosphine (EODPP)

The following starting materials were fed continuously at 80° C. into areactor which was equipped with a three-stage inclined-blade stirrer andhad been made inert with nitrogen: 1) mixture of 110.7 g of ethanol and205.8 g of 1-methylimidazole and 2) chlorodiphenylphosphine (99.4%strength). Stream 1) was added at 330 ml/h and stream 2) was added at380 ml/h. Both streams were introduced below the surface of the liquid.The reactor was equipped with an overflow from which reaction mixturecould flow out continuously. The reactor volume up to the overflow was710 ml. The reaction temperature was maintained at 80° C. To bring thesystem to equilibrium, the output obtained over the first 4 hours wasdiscarded. The output was subsequently collected over a period of 1 hourand a mass balance was carried out. The output consisted of two liquidphases. Over a period of one hour, 497.2 g of upper phase and 280.8 g oflower phase were collected. The upper phase comprised 96.8% of EODPP.The upper phase was subsequently distilled under reduced pressure via acolumn filled with Raschig rings, giving 438.2 g of 99.74% strengthEODPP. Together with the EODPP in the first fraction, the total yieldwas 96.7%.

Example 6 Continuous Preparation of Ethoxydiphenylphosphine (EODPP)

The following feed streams were mixed continuously in a reaction mixingpump: 1) mixture of 159.2 g of 1-methylimidazole and 85.4 g of ethanoland 2) 372.8 g of chlorodiphenylphosphine (99.1% strength). Stream 1)was added at 1257 g/h and stream 2) was added at 1928 g/h. The volume ofthe mixing chamber was 3.3 ml. The top of the reaction mixing pump wasthermostated to 120° C. The system was brought to equilibrium over aperiod of 5 minutes. The output was subsequently collected for 11minutes in order to carry out a mass balance. During the mass balancerun, the amount of starting materials was determined by weighing thereservoirs. 372.8 g of chlorodiphenylphosphine were added. The outputconsisted of two liquid phases. During the 11 minutes, 392.2 g of upperphase and 218.3 g of lower phase were collected. The upper phasecomprised 96.5% of EODPP, so that the yield determined by gaschromatography was 98.2%. The residence time of the reactants in themixing chamber was 4 s, so that the space-time yield was 0.69×10⁶kgm⁻³h⁻¹.

Example 7 Continuous Preparation of Ethoxydiphenylphosphine (EODPP)

The following feed streams were mixed continuously in a reaction mixingpump: 1) mixture of 156.7 g of 1-methylimidazole and 84.1 g of ethanoland 2) 370.0 g of chlorodiphenylphosphine (99.1% strength). Stream 1)was added at 167.5 g/h and stream 2) was added at 257.4 g/h. The volumeof the mixing chamber was 3.3 ml. The top of the reaction mixing pumpwas thermostated to 80° C. The system was brought to equilibrium over aperiod of 60 minutes. The output was subsequently collected for 87minutes in order to carry out a mass balance. During the mass balancerun, the amount of starting materials was determined by weighing thereservoirs. 370.0 g of chlorodiphenylphosphine were added. The outputconsisted of two liquid phases. During the 87 minutes, 389.3 g of upperphase and 219.2 g of lower phase were collected. The upper phasecomprised 96.8% of EODPP, so that the yield determined by gaschromatography was 98.5%. The residence time of the reactants in themixing chamber was 30 s.

Example 8 Continuous Preparation of Diethoxyphenylphosphine (DEOPP)

The following feed streams were mixed continuously in a reaction mixingpump: 1) mixture of 237.1 g of 1-methylimidazole and 127.2 g of ethanoland 2) 225.8 g of dichlorophenylphosphine. Stream 1) was added at 385.6g/h and stream 2) was added at 239.0 g/h. The volume of the mixingchamber was 3.3 ml. The top of the reaction mixing pump was thermostatedto 80° C. The system was brought to equilibrium over a period of 30minutes. The output was subsequently collected for 58 minutes in orderto carry out a mass balance. During the mass balance run, the amount ofstarting materials was determined by weighing the reservoirs. 225.8 g ofdichlorophenylphosphine were added. The output consisted of two liquidphases. During the 58 minutes, 249.0 g of upper phase and 335.6 g oflower phase were collected. The upper phase comprised 95.4% of DEOPP, sothat the yield determined by gas chromatography was 95.5%. The residencetime of the reactants in the mixing chamber was 20 s.

Example 9 Continuous Preparation of Diethoxyphenylphosphine (DEOPP)

The following feed streams were mixed continuously in a reaction mixingpump: 1) mixture of 212.0 g of 1-methylimidazole and 113.7 g of ethanol,2) 201.7 g of dichlorophenylphosphine and 3) recirculated upper phasefrom the reaction output. Stream 1) was added at 1543.5 g/h, stream 2)was added at 955.9 g/h and stream 3) was added at 2377 ml/h. The volumeof the mixing chamber was 3.3 ml. The top of the reaction mixing pumpwas thermostated to 80° C. The system was brought to equilibrium over aperiod of 5 minutes. The output was subsequently collected for 12minutes in order to carry out a mass balance. During the mass balancerun, the amount of starting materials was determined by weighing thereservoirs. 201.7 g of dichlorophenylphosphine were added. The outputconsisted of two liquid phases which were separated in a continuouslyoperated phase separator. Part of the upper phase was recirculated tothe process. During the mass balance run of 12 minutes, 227.0 g of upperphase and 300.6 g of lower phase were collected. The upper phasecomprised 95.2% of DEOPP, so that the yield was 97.2%. The residencetime of the reactants in the mixing chamber was 2.5 s, so that thespace-time yield was 0.36×10⁶ kgm⁻³h⁻¹.

Example 10 Regeneration of 1-methylimidazole Hydrochloride

Using a method analogous to example 1, DEOPP was prepared from 181.5 gof dichlorophenylphosphine, 101.4 g of ethanol and 189 g of1-methylimidazole, giving 202.2 g of an upper phase having a DEOPPcontent of 93.9% and 265.5 g of a lower phase. The upper phase furthercomprised 3.7 g of 1-methylimidazole. The lower phase was mixed with169.6 g of paraffin oil. 168 g of 50% strength aqueous sodium hydroxidesolution were then added dropwise to this mixture, giving a readilystirrable suspension. After the addition of 12.9 g of xylene and 78.4 gof xylene which had been recirculated from a previous experiment andstill contained 3.8 g of 1-methylimidazole, water was distilled offtogether with xylene. A total of 132.7 g of water were removed. When nomore water separated out, xylene was distilled from the reaction mixturevia a 30 cm packed column at 30-85 mbar and 57-90° C. at the top, giving88.4 g of distillate containing 21.8 g of 1-methylimidazole. Thedistillate was reused as recycled xylene in the next experiment, so that1-methylimidazole present therein was always returned to the process.After the xylene distillation, the 1-methylimidazole was distilled offat 30 mbar and 90° C. at the top. 164.0 g of 1-methylimidazole having apurity of 99.7% were recovered. The water content of the distilled1-methylimidazole was 0.06%.

The distillation bottoms were then admixed with 350 g of water todissolve the sodium chloride suspended in the white oil. Two phases wereformed. The 475.7 g of lower phase comprised the sodium chloride and0.3% (1.4 g) of 1-methylimidazole. The 161.1 g of upper phase comprisedthe white oil which was likewise returned to the process as inertsuspension aid. Of the total of 192.8 g of 1-methylimidazole used (189.0g fresh and 3.8 g in the recycled xylene), 164.0 g were recovered aspure substance. A further 21.8 g were present in the distilled xylenewhich was returned to the process, so that the 1-methylimidazole presenttherein was retained. Thus, 185.8 g (96%) of the 1-methylimidazole wereable to be recycled.

Example 11

51 g of acetic acid were dissolved in 120.8 g of cyclohexane. To removethe acid again, 69.80 g of 1-methylimidazole were added to the solution,resulting in formation of a two-phase mixture consisting of 119.4 g ofupper phase (cyclohexane) and 122.5 g of lower phase (ionicliquid=1-methylimidazolium acetate). During the addition of1-methylimidazole, the temperature rose to 40° C. due to salt formation.During the further addition, the temperature was maintained at 40° C. bycooling in an ice bath. After cooling, the acetic acid could beseparated virtually completely in the form of the ionic liquid formedwhich is immiscible with cyclohexane from the solvent by means of aliquid-liquid phase separation.

Example 12 Continuous Preparation of the Following Chelating Phosphonite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) composition: mixture of 11.9 g of 1-methylimidazole, 11.8 g of    o-biphenol and 35.1 g of toluene and-   2) composition: mixture of 38.4 g of    (2-tert-butylphenoxy)chlorophenylphosphine and 153.5 g of toluene.

Stream 1) was added at 681 ml/h and stream 2) was added at 2373 ml/h.The volume of the mixing chamber was 3.3 ml. The top of the reactionmixing pump was thermostated at 120° C. The system was brought toequilibrium over a period of 3 minutes. The output was subsequentlycollected for 7 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction micingpump was 100° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 7 minutes, 233.9 g of upper phase and 14.0 g of lower phase werecollected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The selectivity to the desired chelating phosphonite compared to theundesired monodentate phosphonites was determined by means of 31P-NMRspectra. It was 93.8% in favor of the chelating phosphonite. Theconversion was quantitative.

Example 13

The synthesis of the chelating phosphonite of example 12 was carried outas described in example 12. Various parameters were varied. The top ofthe reaction mixing pump was thermostated so that the final temperaturesof the reaction mixture at the outlet of the pump indicated in the tablecould be obtained. The results are summarized in the following table.Selectivity to chelating phosphonite Temperature over CompositionComposition of Feed Feed at the reactor monodentate of stream 1 stream 2stream 1 stream 2 outlet phosphonites 33.3 g of MIA 106.0 g of TBCP 1603ml/h 1367 ml/h 105.5° C.  96.6% 32.8 g of BP 45.4 g of Tol 98.0 g of Tol37.3 g of MIA 118.7 g of TBCP 1603 ml/h 1367 ml/h 90.5° C. 97.3% 36.7 gof BP 50.9 g of Tol 109.7 g of Tol 41.3 g of MIA 130.9 g of TBCP 1603ml/h 1367 ml/h 76.8° C. 98.6% 40.7 g of BP 56.1 g of Tol 121.6 g of Tol41.3 g of MIA 130.9 g of TBCP 1603 ml/h 1367ml/h 76.8° C. 98.6% 40.7 gof BP 56.1 g of Tol 121.6 g of Tol 21.2 g of MIA 71.2 g of TBCP 1270ml/h 1156 ml/h 76.3° C. 99.3% 20.9 g of BP 30.5 g of Tol 62.5 g of TolMIA = 1-methylimidazoleBP = o-biphenolTol = tolueneTBCP = (2-tert-butylphenoxy)chlorophenylphosphineThe conversion was quantitative in all variants.

Example 14 Continuous Preparation of the Following Chelating Phosphonite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) composition: mixture of 28.0 g of 1-methylimidazole, 36.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 116.4 g of toluene, and-   2) composition: mixture of 88.4 g of    (2-tert-butylphenoxy)chlorophenylphosphine and 37.9 g of toluene.

Stream 1) was added at 1817 ml/h and stream 2) was added at 1153 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 5 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 76.3° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 5 minutes, 264.3 g of upper phase and 40.1 g of lower phase werecollected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The selectivity to the desired chelating phosphonite compared to theundesired monodentate phosphonites was determined by means of 31P-NMRspectra. It was 95.6% in favor of the chelating phosphonite. Theconversion was quantitative. The lower phase (ionic liquid) containedonly about 300 ppm of phosphorus-containing secondary components.

Example 15 Continuous Preparation of the Following Chelating Phosphonite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) composition: mixture of 188.9 g of 1-methylimidazole, 249.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 807.4 g toluene, and-   2) composition: mixture of 664.7 g of    (2-tert-butylphenoxy)-p-fluorophenylchlorophosphine and 284.9 g of    toluene.

Stream 1) was added at 1781 ml/h and stream 2) was added at 1189 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 275 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 69.8° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 275 minutes, 799.6 g of upper phase and 98.9 g of lower phasewere collected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The yield of isolated desired product was 302.9 g (93.4% of theory).

Example 16 Continuous Preparation of the Following Chelating Phosphonite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) mixture of 188.9 g of 1-methylimidazole, 249.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 807.4 g of toluene, and-   2) composition: mixture of 696.1 g of    (2-tert-butyl-6-methylphenoxy)chlorophenylphosphine and 298.3 g of    toluene.

Stream 1) was added at 1730 ml/h and stream 2) was added at 1238 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 275 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 69.5° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 275 minutes, 798.1 g of upper phase and 93.3 g of lower phasewere collected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The yield of isolated desired product was 298.3 g (95.2% of theory).

Example 17 Continuous Preparation of the Following Chelating Phosphite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) mixture of 188.9 g of 1-methylimidazole, 249.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 807.4 g of toluene, and-   2) composition: mixture of 660.5 g of (di-o-cresyl)chlorophosphine    and 283.1 g of toluene.

Stream 1) was added at 1793 ml/h and stream 2) was added at 1176 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 160 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 70.1° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 160 minutes, 470.8 g of upper phase and 60.8 g of lower phasewere collected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The yield of isolated desired product was 166.6 g (93.0% of theory).

Example 18 Continuous Preparation of the Following Chelating Phosphinite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) mixture of 188.9 g of 1-methylimidazole, 249.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 807.4 g of toluene, and-   2) composition: mixture of 445.8 g of diphenylchlorophosphine and    191.1 g of toluene.

Stream 1) was added at 1991 ml/h and stream 2) was added at 906 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 218 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 70.1° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 218 minutes, 641.8 g of upper phase and 93 g of lower phase werecollected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The yield of isolated desired product was 152.3 g (67.4% of theory).

Example 19 Continuous Preparation of the Following Chelating Phosphonite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) mixture of 188.9 g of 1-methylimidazole, 249.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 807.4 g of toluene, and-   2) composition: mixture of 828.1 g of    (2,4-diisoamylphenoxy)chlorophenylphosphine and 354.9 g of toluene.

Stream 1) was added at 1532 ml/h and stream 2) was added at 1395 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 275 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 69° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 275 minutes, 787.9 g of upper phase and 85.3 g of lower phasewere collected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The yield of isolated desired product was 304 g (89.6% of theory).

Example 20 Continuous Preparation of the Following Chelating Phosphonite

The following feed streams were mixed continuously in a reaction mixingpump:

-   1) mixture of 188.9 g of 1-methylimidazole, 249.1 g of    2,2′,4,4′-tetramethyl-o-biphenol and 807.4 g of toluene, and-   2) composition: mixture of 738.3 g of    (2,4-di-tert-butylphenoxy)chlorophenylphosphine and 316.4 g of    toluene.

Stream 1) was added at 1664 ml/h and stream 2) was added at 1308 ml/h.The volume of the mixing chamber was 3.3 ml. The system was brought toequilibrium over a period of 2 minutes. The output was subsequentlycollected for 233 minutes in order to carry out a mass balance. Thetemperature of the reaction medium at the outlet of the reaction mixingpump was 75.8° C. The output consisted of two liquid phases which werecollected in a vessel and subsequently separated. Over the mass balancerun of 233 minutes, 663.9 g of upper phase and 79.8 g of lower phasewere collected. The upper phase was a toluene solution of the reactionproducts, while the lower phase was the hydrochloride of1-methylimidazole which was obtained as an ionic liquid at above 75° C.The yield of isolated desired product was 267 g (94.7% of theory).

Example 21

A mixture of 1.7 mol of PCl₃ and 0.6 mol of AlCl₃ (98% pure) was placedunder an argon atmosphere in a 11 flask which was provided with athermostated jacket, mechanical stirring, thermometer and refluxcondenser at 73° C. 0.4 mol of fluorobenzene was subsequently added overa period of 30 minutes, with a gentle stream of argon being passedthrough the reaction flask. The reaction mixture was stirred for 3hours, cooled to 60° C. and 0.62 mol of N-methylimidazole was slowlyadded over a period of 45 minutes. The reaction was exothermic and mistwas formed. The mixture was subsequently stirred for another 30 minutesat 60° C. When the stirrer was switched off, 2 phases separated. Thelower phase was separated off and the upper phase was extracted twicewith 80 ml each time of PCl₃ at 60° C.

The lower phase and the combined PCl₃ extracts were distilled, giving 55g of p-fluorophenyldichlorophosphine in a yield of 70% of theory and apurity of 96% (determined by ³¹P NMR).

Examples 22-27

The procedure of example 21 was repeated using the ratios offluorobenzene, AlCl₃, PCl₃ and N-methylimidazole indicated in the table.Molar ratio of Molar ratio of AlCl₃:fluoro- N-methyl- Reaction YieldPurity Ex. benzene imidazole:AlCl₃ time [h] [%] [%] 21 1.5 1 3 70 96 221.5 1 6 65 96 23 1.5 1 3 80 91 24 1 1 3 54 96 25 1 0.5 3 16 n.d. 26 1.50.5 3 19 n.d. 27 2 1 3 79 73n.d.: not determined

In example 23, the reaction was carried out in a manner analogous toexample 21, but AlCl₃ of higher purity (>99%) was used.

Comparative Example 3

A mixture of 3.4 mol of PCl₃ and 1.2 mol of AlCl₃ (98% pure) was placedunder an argon atmosphere in a 1 l flask which was provided with athermostated jacket, mechanical stirring, thermometer and refluxcondenser at 73° C. 0.8 mol of fluorobenzene was subsequently added overa period of 30 minutes, with a gentle stream of argon being passedthrough the reaction flask. The reaction mixture was stirred for 3hours, cooled to 60° C. and 1.25 mol of pyridine were slowly added overa period of 45 minutes. The reaction was exothermic and mist was formed.The mixture was subsequently stirred for another 30 minutes at 60° C. Anonuniform solid in the form of large lumps precipitated, and this couldnot be separated off via a suction filter but only by filtration. Thefiltration residue was washed with petroleum ether. The filtrate and thewashings were combined and distilled, giving 73.3 g ofp-fluorophenyldichlorophosphine in a yield of 47% of theory.

Example 28 Acetylation of Pyrrolidine

A solution of 5.88 g (75.0 mmol) of acetyl chloride in 10 ml of MTBE wasadded dropwise at 10-15° C. to a solution of 5.33 g (75.0 mmol) ofpyrrolidine in 20 ml of MTBE (tert-butyl methyl ether), with thetemperature being maintained. The suspension formed was admixed with6.75 g (82.5 mmol) of 1-methylimidazole while cooling in ice and themixture was then warmed to 20° C., resulting in the suspension beingconverted into a liquid two-phase mixture. This mixture was stirred foranother 1 hour and the phases were separated. The upper phase was freedof solvent on a rotary evaporator to give 6.28 g (74.1%) ofN-acetylpyrrolidine. The lower phase comprised further target producttogether with 1-methylimidazole hydrochloride. The lower phase wasextracted twice with dichloromethane, giving, after addition of water,another 1.70 g (20.1%) of N-acetylpyrrolidine.

Example 29 Acetylation of 1-butanol

6.47 g (82.5 mmol) of acetyl chloride were added dropwise to a solutionof 5.55 g (75.0 mmol) of 1-butanol and 6.67 g (82.5 mmol) of1-methylimidazole while stirring and cooling in ice at such a rate thatthe temperature did not exceed 10° C. The reaction mixture was thenheated to 75° C., forming a liquid two-phase mixture. The upper phasewas separated off and was found to consist of 6.73 g (77.5%) of 1-butylacetate containing, according to analysis by GC, about 1% of1-methylimidazole. The lower phase solidified on cooling to 20° C.

Example 30 Acetylation of 2-butanol

6.47 g (82.5 mmol) of acetyl chloride were added dropwise to a solutionof 5.55 g (75.0 mmol) of 2-butanol and 12.3 g (150 mmol) of1-methylimidazole while stirring and cooling in ice at such a rate thatthe temperature did not exceed 10° C. The mixture was then stirred for30 minutes at 0° C. and for another 30 minutes at 20° C. This resultedin the suspension initially formed being converted into a liquidtwo-phase mixture. The upper phase was separated off to give 7.90 g(theory: 8.68 g) of 2-butyl acetate as a colorless oil having a purityof 85% (GC).

Example 31 Acetylation of Isobutanol (2-methylpropan-1-ol)

6.47 g (82.5 mmol) of acetyl chloride were added dropwise to a solutionof 5.55 g (75.0 mmol) of isobutanol and 6.76 g (82.5 mmol) of1-methylimidazole while stirring at 20° C. The reaction mixture wasstirred for a further 30 minutes and subsequently heated to 75° C. Thisresulted in the suspension initially formed being converted into aliquid two-phase mixture. The upper phase was separated off to give 7.01g (theory: 8.68 g) of isobutyl acetate as a colorless oil having apurity of 99% (GC).

Example 32 Acetylation of Neopentyl Alcohol (2,2-dimethyl-1-propanol)

6.47 g (82.5 mmol) of acetyl chloride were added dropwise to a solutionof 6.61 g (75.0 mmol) of neopentyl alcohol (2,2-dimethyl-1-propanol) and6.76 g (82.5 mmol) of 1-methylimidazole while stirring at 20° C. Thereaction mixture was stirred for a further 30 minutes and subsequentlyheated to 75° C. This resulted in the suspension initially formed beingconverted into a liquid two-phase mixture. The upper phase was separatedoff to give 8.40 g (theory: 9.76 g) of neopentyl acetate as a colorlessoil having a purity of 98% (GC).

Example 33 Benzoylation of n-butanol

11.9 g (82.5 mmol) of benzoyl chloride were added dropwise to a solutionof 5.55 g (75.0 mmol) of 1-butanol and 6.76 g (82.5 mmol) of1-methylimidazole while stirring at 10° C. The reaction mixture wasstirred for a further 30 minutes and subsequently heated to 75° C. Thisresulted in the suspension initially formed being converted into aliquid two-phase mixture. The upper phase was separated off to give 9.90g (theory: 13.3 g) of 1-butyl benzoate as a colorless oil having apurity of 99% (GC).

Example 34 Palmitoylation of Prenol

A solution of 20.6 g (75.0 mmol) of palmitoyl chloride (C16) in 10 ml oftoluene was added dropwise to a solution of 6.46 g (75.0 mmol) of prenol(3-methylbut-2-en-1-ol) and 6.76 g (82.5 mmol) of 1-methylimidazole in40 ml of toluene while stirring at 20-36° C. The reaction mixture wasstirred for a further 30 minutes and subsequently heated to 80° C. Thisresulted in the suspension initially formed being converted into aliquid two-phase mixture. The upper phase was separated off andevaporated on a rotary evaporator to give 23.6 g (theory: 24.3 g) ofprenyl palmitate as a solid-liquid mass having a purity of 95% (GC).

Example 35 Palmitoylation of All-trans-retinol (Vitamin-A Alcohol, VAA)

In the absence of light and while cooling, palmitoyl chloride (170.0 g,0.618 mol) (C16) was added dropwise to a 29% strength solution ofall-trans-retinol in heptane (608.5 g, 0.616 mol) and 1-methylimidazole(50.8 g, 0.62 mol) over a period of 25 minutes while stirring. Thereaction temperature rose to 15° C. The mixture was stirred for 30minutes at 2-5° C., and then for 30 minutes at room temperature. Themixture was heated to 90° C., resulting in two liquid phases beingformed. The phases were separated. The upper phase comprised, apart fromthe solvent, 0.27% of retinol and 95.2% of vitamin A palmitate (HPLC).

Example 36 Acylation of Ethylhexanoyl Chloride

2-Ethylhexanoyl chloride (30.0 g, 0.186 mol) is slowly added at 10-15°C. to a solution of 4-(hydroxymethyl)-1,3-dioxolan-2-one (20.0 g, 0.169mol) and 1-methylimidazole (MIA, 30.6 g, 0.373 mol) in methylenechloride (400 ml) under a nitrogen atmosphere and while cooling in ice.The reaction mixture is stirred overnight and the solvent is removedunder reduced pressure. The residue is taken up in methyl tert-butylether (MTBE) twice and the phases are separated in each case. Theorganic upper phase is evaporated under reduced pressure. This gives theester as a colorless oil containing residual MIA. The mixture is takenup in toluene twice and the solvent is in each case removed underreduced pressure. This gives 45.83 g of a yellowish oil having a MIAcontent of 17% (NMR).

Example 37 Silylation of n-butanol

4.40 g (40.5 mmol) of chlorotrimethylsilane were added dropwise to asolution of 3.00 g (40.5 mmol) of 1-butanol and 11.1 g (135 mmol) of1-methylimidazole while stirring at 0° C. The reaction mixture wasstirred for another 15 minutes at 0-5° C. and for 15 minutes at 20° C.,resulting in the formation of a liquid two-phase mixture. The upperphase was separated off to give 5.30 g (theory: 5.93 g) of1-trimethylsilyloxybutane as a colorless oil having a purity of 90%(GC).

Example 38 Silylation of 2-butanol

8.06 g (74.2 mmol) of chlorotrimethylsilane were added dropwise to asolution of 5.00 g (67.5 mmol) of 2-butanol and 6.10 g (74.2 mmol) of1-methylimidazole while stirring at 0° C. The reaction mixture wasstirred for another 30 minutes at 0° C. and for 5 minutes at 80° C.,resulting in the formation of a liquid two-phase mixture. The upperphase was separated off to give 8.50 g (theory: 9.88 g) of2-trimethylsilyloxybutane as a colorless, slightly turbid oil having apurity of 96% (GC).

Example 39 Silylation of Neopentyl Alcohol (2,2-dimethyl-1-propanol)

6.50 g (56.7 mmol) of chlorotrimethylsilane were added dropwise to asolution of 5.00 g (56.7 mmol) of neopentyl alcohol(2,2-dimethyl-1-propanol) and 11.6 g (142 mmol) of 1-methylimidazolewhile stirring at 0° C. The reaction mixture was stirred for a further 2hours at 0° C. and for 2.5 hours at 20° C. The upper phase was separatedoff to give 7.80 g (theory: 9.09 g) of2,2-dimethyl-1-trimethylsilyloxypropane as a colorless oil having apurity of 96% (GC).

Example 40 Silylation of Benzyl Alcohol

5.50 g (51.0 mmol) of chlorotrimethylsilane were added dropwise to asolution of 5.00 g (46.0 mmol) of benzyl alcohol and 4.20 g (51.0 mmol)of 1-methylimidazole while stirring at 0° C. The reaction mixture wasstirred for a further 30 minutes at 0° C. and for 5 minutes at 80° C.,resulting in the formation of a liquid two-phase mixture. The upperphase was separated off to give 7.30 g (theory: 8.29 g) of benzyltrimethylsilyl ether as a colorless oil having a purity of 99% (GC).

Example 41 Reaction of Ethanol with Silicon Tetrachloride

SiCl₄ (50.0 g, 0.294 mol) is slowly added to a solution of ethanol (54.3g, 1.17 mol) and 1-methylimidazole (MIA, 98.9 g, 1.21 mol) in heptane(400 ml) while cooling in ice and under an N₂ atmosphere. The reactionmixture is stirred overnight and the phases are separated. This gives142.9 g of MIA hydrochloride as a colorless solid (theory: 141.9 g ofMIA+MIA.HCl). The organic phase is carefully evaporated to keep lossesof volatile product low. This gives 48.1 g of tetraethoxysilane (theory:61.3 g) as a slightly turbid, colorless oil having a purity of 91.1%(GC).

Example 42 Silylation of Acetylacetone

5.97 g (55.0 mmol) of chlorotrimethylsilane were added dropwise to asolution of 5.00 g (49.9 mmol) of acetylacetone and 4.50 g (55.0 mmol)of 1-methylimidazole while stirring at 0° C. The reaction mixture wasstirred for another 1 hour at 0° C. and for 5 minutes at 80° C.,resulting in the formation of a liquid two-phase mixture. The upperphase was separated off to give 7.00 g (theory: 8.60 g) of4-trimethylsilyloxypent-3-en-2-one as a light-yellow, turbid oil havinga purity of 84% (GC).

Example 43 Elimination of Hydrogen Bromide from 3-bromocyclohexene

A solution comprising 10.0 g (62.1 mmol) of 3-bromocyclohexane and 12.4g (62.2 mmol) of N,N-dibutylpentylamine was stirred at 120° C. for 1hour, cooled to 25° C. and admixed with 30 ml of n-pentane. The mixturewas heated to 30° C., resulting in the formation of a liquid two-phasemixture. The phases were separated and the lower phase was extractedwith 30 ml of n-pentane. The pentane phases were combined and thepentane was distilled off on a rotary evaporator (20° C., 400-500 mbar),leaving 3.50 g (theory: 4.97 g) of a colorless residue which, accordingto GC, consisted predominantly of 1,3-cyclohexadiene.

Example 44 Comparison Synthesis of bis(N-3-methylindolyl)chlorophosphine(=bisskatylchlorophosphine)

28.5 g (218 mmol) of 3-methylindole (skatole) together with about 50 mlof dried toluene were placed in a vessel and the solvent was distilledoff under reduced pressure to remove traces of water by azeotropicdistillation. This procedure was repeated once more. The residue wassubsequently taken up in 700 ml of dried toluene under argon and cooledto −65° C. 14.9 g (109 mmol) of PCl₃ followed by 40 g (396 mmol) oftriethylamine were then slowly added at −65° C. The reaction mixture wasbrought to room temperature over a period of 16 hours and then refluxedfor 16 hours. ³¹P NMR (reaction mixture, 298 K): δ=102. Purity accordingto 31p NMR=about 90-95%.

Example 45 Comparison Synthesis of Ligand A

28.5 g (218 mmol) of 3-methylindole (skatole) together with about 50 mlof dried toluene were placed in a vessel and the solvent was distilledoff under reduced pressure to remove traces of water by azeotropicdistillation. This procedure was repeated once more. The residue wassubsequently taken up in 700 ml of dried toluene under argon and cooledto −65° C. 14.9 g (109 mmol) of PCl₃ followed by 40 g (396 mmol) oftriethylamine were then slowly added at −65° C. The reaction mixture wasbrought to room temperature over a period of 16 hours and then refluxedfor 16 hours. 19.3 g (58 mmol) of4,5-dihydroxy-2,7-di-tert-butyl-9,9-dimethylxanthene in 300 ml of driedtoluene were added to the reaction mixture, and the mixture was thenrefluxed for 16 hours, cooled to room temperature and the colorlesssolid which had precipitated (triethylamine hydrochloride) was filteredoff with suction, the solvent was distilled off and the residue wasrecrystallized twice from hot ethanol. Drying under reduced pressuregave 36.3 g (71% of theory) of a colorless solid. ³¹P NMR (298K): δ=105.

Example 46 Continuous Synthesis of bis(3-methylindolyl)chlorophosphine

15.9 g (0.12 mol) of 3-methylindole (skatole) were dissolved in 22 g(0.27 mol) of 1-methylimidazole and 69 g of dried toluene (solution I).In addition, 8.2 g (0.06 mol) of phosphorus trichloride were mixed with67 g of dried toluene (solution II). The two solutions (I and II) weremixed continuously at 90° C. in a reaction mixing pump. Stream I was fedin at a rate of 1735 ml/h, and stream II was fed in at a rate of 1235ml/h. The volume of the mixing chamber was 3.3 ml. The system wasbrought to equilibrium for 3 minutes, and the output was subsequentlycollected. The output consisted of two liquid phases which wereseparated by decantation. ³¹P NMR (crude solution, 298 K): δ=97. Purityaccording to ³¹P NMR=about 95%.

Example 47 Continuous Synthesis of Ligand A

Procedure

25.3 g (0.071 mol) of4,5-dihydroxy-2,7-di-tert-butyl-9,9-dimethylxanthene were dissolved in84 g of toluene with addition of 84.2 g (1.03 mol) of 1-methylimidazole(solution I). 48.7 g of bis(N-3-methylindolyl)chlorophosphine in 84.3 oftoluene were prepared in accordance with method 5.1, with the ammoniumsalt formed in the synthesis being separated under protective gas bymeans of a frit (solution II). The two solutions (I and II) were mixedcontinuously at 90° C. in a reaction mixing pump. Stream I was fed in ata rate of 1767 ml/h, and stream II was fed in at a rate of 1203 ml/h.The volume of the mixing chamber was 3.3 ml, and the residence time wasaccordingly about 4 s. The system was brought to equilibrium for 3minutes, and the output was subsequently collected. The output consistedof two liquid phases (N-methylimidazolium chloride and solvent/product).The upper phase, which comprised the product, was decanted off andevaporated under reduced pressure. The residue was refluxed in ethanoland the clear, yellow solution was then cooled to room temperature,resulting in precipitation of a solid which was filtered off withsuction, then washed with ethanol and subsequently dried at reducedpressure. This gave 27.3 g (41% of theory) of a colorless solid. ³¹P NMR(CDCl₃, 298K): δ=106.

Fine Purification:

If traces of N-methylimidazole influence the catalysis, they can beremoved by washing a solution of the ligand in an organic solvent withwater.

56.8 g of the colorless solid (ligand A) were dissolved in 500 ml ofdiethyl ether and washed six times with 20 ml each time of saturatedaqueous sodium hydrogencarbonate solution. The solution was subsequentlywashed twice more with 15 ml each time of water, the organic phase wasseparated off, volatile constituents were removed under reduced pressureand the residue was washed with 300 ml of ethanol. Drying under reducedpressure gave 48.1 g of a colorless solid. ³¹P NMR (CDCl₃, 298K): δ=106.

Example 48 Continuous Synthesis of Ligand A

Procedure:

25.3 g (0.07 mol) of4,5-dihydroxy-2,7-di-tert-butyl-9,9-dimethylxanthene were dissolved in84 g of toluene with addition of 84 g (1.03 mol) of 1-methylimidazole(solution I). 48.5 g (0.14 mol) of bis(N-3-methylindolyl)chlorophosphinein 84 g of toluene were prepared in accordance with method 5.1, with theammonium salt formed in the synthesis being separated under protectivegas by means of a frit (solution II). The two solutions (I and II) weremixed continuously at 90° C. in a reaction mixing pump. Stream I was fedin at a rate of 589 ml/h, and stream II was fed in at a rate of 401ml/h. The volume of the mixing chamber was 3.3 ml, and the residencetime was accordingly about 12 s. The system was brought to equilibriumfor 3 minutes, and the output was subsequently collected. The outputconsisted of two liquid phases (N-methylimidazolium chloride andsolvent/product). The upper phase, which comprised the product, wasdecanted off and evaporated under reduced pressure. The residue wasrefluxed in ethanol and the clear, yellow solution was then cooled toroom temperature, resulting in precipitation of a solid which wasfiltered off with suction, then washed with ethanol and subsequentlydried at reduced pressure. This gave 30.5 g (46% of theory) of acolorless solid. ³¹P NMR (CDCl₃, 298K): δ=106.

Example 49 Comparison: Hydroformylation of 1-butene from a ConventionalSynthesis (Example 45)

5.5 mg of Rh(CO)₂acac (acac=actetylacetonate) and 200 mg of ligand Awere weighed out separately, each dissolved in 5 g of toluene, mixed andtreated with 10 bar of synthesis gas (CO:H₂=1:1) at 90° C.(preactivation). After 1 hour, the autoclave was depressurized. 9.9 g of1-butene were then added via a pressure lock, a total pressure of 17 barwas set by means of synthesis gas (CO:H₂=1:1) and hydroformylation wascarried out for 2 hours at 90° C. (109 ppm of Rh; ligand A:Rh=10:1).After the reaction time indicated, the autoclave was cooled, carefullydepressurized via a cold trap and both reaction product mixtures(reactor and cold trap) were analyzed by means of gas chromatography.The conversion was 99%, the yield of valeraldehyde was 92% and thelinearity (proportion of n product) was 98.5%. The linearity (proportionof n product) is defined as the amount of n-valeraldehyde divided by thetotal amount of n-valeraldehyde and i-valeraldehyde multiplied by 100.

Example 50 Comparison: Hydroformylation of 2-butene at CO:H₂=1:2 from aConventional Synthesis (Example 45)

5.0 mg of Rh(CO)₂acac (acac=actetylacetonate) and 176 mg of ligand Awere weighed out separately, each dissolved in 5 g of toluene, mixed andtreated with 10 bar of synthesis gas (CO:H₂=1:2) at 90° C.(preactivation). After 1 hour, the autoclave was depressurized. 11.2 gof 2-butene were then added via a pressure lock, and a total pressure of17 bar was set by means of synthesis gas (CO:H₂=1:2). The gas introducedwas then changed over to synthesis gas (CO:H₂=1:1). Hydroformylation wassubsequently carried out at 90° C. for 4 hours (93 ppm of Rh; ligandA:Rh=10:1). The conversion was 34%, the yield of valeraldehyde was 32%and the linearity (proportion of n product) was 93%.

Example 51 Hydroformylation of 1-butene Using Ligand A from a ReactionMixing Pump (Example 47)

5 mg of Rh(CO)₂acac (acac=actetylacetonate) and 200 mg of ligand A wereweighed out separately, each dissolved in 5 g of toluene, mixed andtreated with 10 bar of synthesis gas (CO:H₂=1:1) at 90° C.(preactivation). After 1 hour, the autoclave was depressurized. 12.5 gof 1-butene were then added via a pressure lock, and a total pressure of17 bar was set by means of synthesis gas (CO:H₂=1:1) andhydroformylation was carried out at 90° C. for 2 hours (88 ppm of Rh;ligand A:Rh=11:1). After the reaction time indicated, the autoclave wascooled, carefully depressurized via a cold trap and both reactionproduct mixtures (reactor and cold trap) were analyzed by means of gaschromatography. The conversion was 99%, the yield of valeraldehyde was98% and the linearity (proportion of n product) was 96.3%.

Example 52 Hydroformylation of 2-butene Using Ligand A from a ReactionMixing Pump (Example 47)

5.0 mg of Rh(CO)₂acac (acac=actetylacetonate) and 118 mg of ligand Awere weighed out separately, each dissolved in 5 g of toluene, mixed andtreated with 10 bar of synthesis gas (CO:H₂=1:2) at 90° C.(preactivation). After 1 hour, the autoclave was depressurized. 11.8 gof 2-butene were then added via a pressure lock, and a total pressure of17 bar was set by means of synthesis gas (CO:H₂=1:2). The gas introducedwas then changed over to synthesis gas (CO:H₂=1:1). Hydroformylation wassubsequently carried out at 90° C. for 4 hours (91 ppm of Rh; ligandA:Rh=7:1). The conversion was 29%, the yield of valeraldehyde was 26%and the linearity (proportion of n product) was 93.8%.

Example 53 Continuous Synthesis of Phenoxyphenylchlorophosphines

100 g (0.66 mol) of 2-tert-butylphenol are dissolved in 102 g ofmesitylene with addition of 54.1 g (0.66 mol) of 1-methylimidazole(solution I). Solution I was continuously mixed at a flow rate of 4432.1ml/h with solution II consisting of 121.6 g (0.66 mol) ofdichlorophenylphosphine in a reaction mixing pump. Solution II was fedin at a rate of 1507.9 ml/h. The top of the reaction mixing pump washeated to 100° C. in an oil bath. The volume of the mixing chamber was3.3 ml, and the residence time was accordingly about 2 s. The system wasbrought to equilibrium for 3 minutes and the output was subsequentlycollected. The output consisted of two liquid phases (product/solventand 1-methylimidazolium hydrochloride). The upper, product-containingphase was decanted off. GC: 2-tert-butylphenoxyphenylchlorophosphine:60% by area.

1-16. (canceled) 17: A method of removing an acid from a reactionmixture, comprising: providing said reaction mixture containing saidacid; reacting said acid and an auxiliary base to form a salt of theauxiliary base; said salt being liquid at temperatures at which adesired product of said reaction mixture is not significantly decomposedduring the process of separating off the liquid salt; forming twoimmiscible liquid phases, a first phase comprising said salt of theauxiliary base and a second phase comprising said desired product or asolution of said desired product in a solvent; firstly, distilling offthe desired product from the reaction mixture in the presence of theauxiliary base in the protonated form; then setting free the auxiliarybase using a strong base, to obtain a free auxiliary base; anddistilling the free auxiliary base. 18: A method of removing an acidfrom a reaction mixture, comprising: providing said reaction mixturecontaining said acid; reacting said acid and an auxiliary base to form asalt of the auxiliary base; said salt being liquid at temperatures atwhich a desired product of said reaction mixture is not significantlydecomposed during the process of separating off the liquid salt; formingtwo immiscible liquid phases, a first phase comprising said salt of theauxiliary base and a second phase comprising said desired product or asolution of said desired product in a solvent; firstly, setting free theauxiliary base using a strong base, to obtain a free auxiliary base;distilling the free auxiliary base in the presence of the desiredproduct; and then distilling the desired product. 19: A method ofstopping an acid-catalyzed reaction, comprising: neutralizing an acidcatalyst in a chemical reaction mixture with an auxiliary base, to forma salt of the auxiliary base; said salt being liquid at temperatures atwhich a desired product of said reaction mixture is not significantlydecomposed during the process of separating off the liquid salt; formingtwo immiscible liquid phases, a first phase comprising said salt of theauxiliary base and a second phase comprising said desired product or asolution of said desired product in a solvent. 20: The method as claimedin claim 17, wherein the salt of the auxiliary base has a melting pointbelow 160° C. 21: The method as claimed in claim 17, wherein the salt ofthe auxiliary base has an E_(T)(30) of more than
 35. 22: The method asclaimed in claim 17, wherein the base contains at least one nitrogenatom. 23: The method as claimed in claim 17, wherein the base used isselected from the group consisting of compounds of the formulae (Ia) to(Ir),

wherein R¹, R², R³, R⁴, R⁵ and R⁶ are each, independently of oneanother, hydrogen, C₁-C₁₈-alkyl, C₂-C₁₈-alkyl which may be interruptedby one or more oxygen and/or sulfur atoms and/or one or more substitutedor unsubstituted imino groups, C₆-C₁₂-aryl, C₅-C₁₂-cycloalkyl or a five-to six-membered, oxygen, nitrogen- and/or sulfur-containing heterocycle,wherein each of the abovementioned radicals may be substituted byfunctional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatomsand/or heterocycles. 24: The method as claimed in claim 17, wherein theauxiliary base is 1-n-butylimidazole, 1-methylimidazole,2-methylpyridine or 2-ethylpyridine. 25: The method as claimed in claim17, wherein the auxiliary base is di-n-butyl-n-pentylamine or1,5-diazabicyclo[4.3.0]non-5-ene (DBN). 26: The method as claimed inclaim 17, wherein the salt of the auxiliary base is soluble to an extentof less than 20% by weight in the desired product or in the solution ofthe desired product in a suitable solvent. 27: The method as claimed inclaim 17, wherein diphosphorous diester amides ([N](R′O)P—O-Z-O—P[N′](OR″)), diphosphorous ester diamides ([N][N′]P—O-Z-O—P[N″][N′″]),bistriaminophosphines ([N][N′]P—[N″]-Z-[N′″]—P[N″″][N′″″]), or systemsof the formula [N](R′O)P—O-Z-O—P(OR″)(OR′″), [N][N′]P—O-Z-O—P(OR″)(OR′″)or [N][N′]P—O-Z-O—P[N″](OR′″) or systems which are both nitrogen- andcarbon-substituted on each phosphorus and have the formula[N](R′)P—O-Z-O—P[N′](R′″) or [N](R′)P—[N″]-Z-[N′″]—P[N′](R′″) or systemsof the formula [N](R′O)P—O-Z-O—P[N′](R′″) are prepared, wherein R, R′,R″ and R′″ can be any organic radicals which may be identical ordifferent, [N], [N′], [N″], [N′″], [N″″] and [N′″″] are unsubstituted,monosubstituted or disubstituted amino groups which may be identical ordifferent and Z can be any divalent bridge. 28: The method of claim 17,wherein the preparation is carried out continuously at from 30° C. to190° C. and a residence time of from 1 second to 1 hour.